Cannabis—also known as marijuana, pot, herb and weed—is a plant with dried flowering leaves, buds, seeds and stems that are used in medicine, manufacturing and as a recreational drug.

Humans have been using cannabis for hundreds of years primarily for fiber, (popularly known as hemp), seed oil, medical purposes and for recreation.
It is predominantly smoked, vaped, absorbed under the tongue or swallowed. It can also be applied directly to the skin.

The history of cannabis use has been marked by restriction, especially since the beginning of the 20th century. Many countries continue to have strict rules on possession, use or sale of marijuana, thus rendering it illegal in those places.
In other places, herb is readily available, with several countries and states having legalized cannabis for recreational or medical purposes.
In 2018, Canada legalized this herbal substance at the federal level, ushering in a new era for users. This article will cover all you need to know about cannabis, from the different types of plants, to cannabis plant anatomy, to modern uses for the cannabis plant.

What is Cannabis?

Cannabis is a term that broadly refers to a genus of flowering plants in the cannabaceae family.  To define cannabis as a drug used for recreational and medical purposes, while true, fails to tell the whole story. In fact, cannabis has been used as a significant material in textiles and as food throughout history in the form of hemp. Hemp, however, is very low in both THC and CBD, the two major molecules of therapeutic and recreational interest. So for the purpose of this article we will be referring primarily to cannabis that is cultivated for medicinal and recreational purposes as opposed to fiber and food.

So how is medicinal and recreational cannabis different from hemp? When people ask “what is cannabis?”, they are really asking about a medicine or a recreational drug with a wide range of psychoactive and physiologic effects. The part of the plant we are generally talking about is the clusters of flowers cannabis plants produce, a mass often referred to as the cola.

Flower, or bud, can be smoked or vaporized in dry form, but is also commonly extracted to produce a concentrated form. Other materials from the plant such as the stems and leaves may also be used, although these parts contain much less of the active ingredients. In Canada, these extracts are often diluted with a carrier oil before being sold by licensed producers.

How many types of Cannabis are there? 

That depends on how you classify Cannabis. This plant is often categorized a number of different ways, for example:

  • By strain (Indica, Sativa, hybrid)
  • By cannabinoid content (CBD%, THC%)
  • By its form or administration method (oil, hash, wax, flower, milled, edible, capsule, smoke, vape)
  • By terpene content (limonene, ocimene, linalool, myrcene)

Marijuana Types Indica and Sativa

The most common way people classify cannabis is by identifying a strain as either an Indica, a Sativa or some form of hybrid. We won’t get into the botanical debate about whether these represent distinct species or not but rather focus on some of the current thinking about classifying cannabis this way.   

Sativa Plant versus Indica Plant

When we talk about Sativa and Indica varieties we are really talking about the way the plant looks. This is called the morphology or phenotype. Tall with thin leaves vs short with wide leaves. By simply looking at cannabis plants you might be tempted to classify them this way. But this classification is not very scientific and does not adequately describe or classify the plants by their effect on the human body. Modern plants have been cross bred so many times that some may look like an indica plant but chemically have a great deal of sativa properties.

Although these two types of cannabis are very different in appearance, their chemical makeup or chemotype is really what we are interested in when we think about cannabis as medicine. This is so much more important than the way the plants look or how they are prone to grow differently.  

In a 2016 interview, Dr. Ethan Russo, neurologist and psychopharmacology researcher stated,

“There are biochemically distinct strains of Cannabis, but the sativa/indica distinction as commonly applied in the lay literature is total nonsense and an exercise in futility. One cannot in any way currently guess the biochemical content of a given Cannabis plant based on its height, branching, or leaf morphology.”

Dr. Russo further goes on to explain,

“Sedation in most common Cannabis strains is attributable to their myrcene content, a monoterpene with a strongly sedative couch-lock effect that resembles a narcotic. In contrast, a high limonene content (common to citrus peels) will be uplifting on mood, while the presence of the relatively rare terpene in Cannabis, alpha-pinene, can effectively reduce or eliminate the short-term memory impairment classically induced by THC.”

Cannabis Plant Overview

One of the most interesting things about cannabis is that it is dioecious, which means there are separate female and male plants. Most plants have both male and female traits within a single plant but cannabis has two distinct sexes. Male plants produce pollen sacs that fertilize the females, which in turn grow seed pods.

But female plants don’t need to be pollinated to produce marijuana. In fact, unpollinated female plants tend to produce flowers that are more resinous and richer in terpenes and cannabinoids as they are able to put all of their growth energy into producing medicine rather than seeds. The technique of growing cannabis while keeping male and female plants separated leads to females growing large flowers with no seeds. This technique is called “sin semilla” which is Spanish for “without seeds”.

These flowers or buds form together to make colas. Sometimes the cola at the top of the female plant is the most significant. It may be comprised of hundreds of tiny flowers and in full grown plants can exceed 4 feet by the time it is ready to be harvested. Smaller buds and colas can form all over the plant and contain the highest concentration of medicine. Contrary to popular belief the typical and well recognized cannabis leaf contains relatively little medicine. 

Each cannabis flower is densely covered in glandular trichomes which secrete marijuana’s medicinal resin. These glands carry the majority of the terpenoids and cannabinoids that we use medicinally.

What might Cannabis be used for?

There is a lot of research underway to understand if cannabis may be useful to treat a variety of conditions including:

  • Chronic pain
  • PTSD
  • Seizures
  • Anxiety
  • Autism
  • Multiple sclerosis
  • Cancer

Scientific research on cannabis as a medicine is understood to have faced significant setbacks due to the history of restrictions imposed on production and possession in countries across the globe. Many doctors and health care providers feel there is not yet enough evidence to support the use of cannabis in treating certain conditions. In other conditions, there is more evidence and the use of cannabis has become more accepted.

As medicinal cannabis becomes used more often, there is a great opportunity to gather data on the benefits and potential risk of this medicine moving forward.

At Weedwell™ we support the notion that much more research is needed to fully unlock the therapeutic potential of the cannabis plant as well as to identify possible harms of using cannabis as medicine.

As with many medications there are both potential benefits and side effects.

Depending on the way it is administered, potency and individual circumstances immediate side effects of using cannabis may include:

  • dry mouth
  • decrease in short-term memory
  • paranoia
  • poor coordination
  • red eyes
  • anxiety
  • blood pressure changes

Long-term side effects can include both mental and physical problems including but not limited to, cognitive impairment, addiction and bronchitis

At Weedwell™ we encourage you to resist the temptation to self-medicate and speak with a medical professional first. A trained doctor can help you take a measured approach to cannabis dosage and select the right strains according to your unique condition.

Marijuana Cannabinoids

Cannabis contains hundreds of chemical compounds. Of these, cannabinoids are perhaps the most interesting part of the cannabis plant from the perspective of medical researchers.

The exact number of cannabinoids in cannabis is not known, but there are more than 60 types. These molecules all originate from the cannabinoid CBGA and by conversion through a number of reactions, turn into THC, CBD and a host of other molecules that work with terpenes and flavonoids to produce clinical effects.


THC is the component of cannabis that gets people high, and can cause problems with paranoia, anxiety, coordination etc. CBD does not get people high.

Does medical marijuana contain THC? 

Yes and No. Simple answer eh?

Even if we are trying to use as pure a CBD strain as we can find, there is still minute quantities of THC in the plant. Although the patient might not notice this small amount of THC, it can show up in a urine or blood test. Only pure CBD isolates that are certified as free of THC can be guaranteed not to contain THC.  

So, medical marijuana does have THC except in rare cases, but these levels can be as low as 0.4%. More often CBD dominant strains will still have 2-10% THC.

When you draw a comparison between THC and cannabinoids like CBD or CBC, the main thing to keep in mind is that THC has psychoactive effects.

Are there medical uses for THC?

Absolutely!  Although the majority of our clients at Weedwell™ use CBD rich products, this does not mean that there is no place for THC as medicine. Neuropathic pain for example seems to respond best to THC as opposed to CBD. We also feel people who have pain at night sleep better with THC than with CBD as CBD can be mildly alerting.

Those clients that choose CBD typically want to ensure they are not impaired during the daytime so they can work and drive safely. If they require more symptom relief than CBD can provide, we will often add a bit of THC to an evening dose of CBD.

Please remember, this is not medical advice and that we feel there are pitfalls that only a qualified clinician can identify both in the use of CBD and THC based products. (Click here to read about CBD interactions) https://weedwell.com/blog/cbd-interactions-breast-cancer-tamoxifen/


Intensive research on medical cannabis is underway to understand its utility for disease states ranging from autoimmune conditions, infection, inflammation, pain, epilepsy, psychiatric conditions, withdrawal and addiction. Researchers are even looking at marijuana’s potential to kill cancer cells.

In the meantime, follow us on your favorite media channels. Our goal is to deliver quality information and updates on medical cannabis.

Please rate this


  • Piomelli D, Russo EB (2016) The Cannabis sativa

    versus Cannabis indica debate: an interview with Ethan Russo, MD,

    Cannabis and Cannabinoid Research 1:1, 44–46

View More



Submit a Comment

Your email address will not be published. Required fields are marked *

Related Articles

Sharing is Caring

Help spread the word. You're awesome for doing it!