CBD Oil Side Effects

In recent years there has been considerable interest in the use of CBD for health, wellness and other purposes. Today, more than one-third of all Americans have used CBD, with nearly 14% consuming this naturally occurring cannabinoid regularly. Expand those stats to the global population and you have what has become a $20 billion industry.

However, many consumers have concerns or questions about CBD oil side effects (if any exist), signs of symptoms, what to look out for, and whether or not they should be concerned.

Although this is a conversation best had with your doctor, this guide is meant to be an educational and informational starting point, highlighting clinical studies, scientific research, and advice from organizations such as the World Health Organization (WHO), and the US Food and Drug Administration (FDA).

What is CBD?

CBD (cannabidiol) is the second most prevalent cannabinoid present in both Cannabis and hemp. The majority of CBD on the market is derived from industrial hemp, and contains less than 0.3% THC.

Although research is ongoing, CBD has shown incredible promise as a potential therapeutic aid for a wide range of conditions and purposes. To date, the FDA has only approved CBD for the use of treating certain forms of Epilepsy.

As a non-psychoactive cannabinoid, CBD is attractive to those who wish to harness the potential wellness and health properties of cannabis, without the ‘high’ attributable to marijuana and THC.

This has also sparked interest from the medical and scientific community, both of which are studying the potential applications of CBD in pharmacological research dating back to the 1970s, and experiencing a blockbuster resurgence with the passing of the 2018 Farm Bill in the USA.

A big part of studying a potential therapeutic aid is evaluating its safety profile, and potential side effects.


The World Health Organization and Others Weigh in on the Safety and Side Effects of CBD

Safety and Toxicological Side Effects of CBD

Toxicology is a branch of science that studies the detection, nature and effects of substances determined to be poisonous if exposed to or ingested. There have been extensive toxicological studies conducted on CBD, the results of which have determined that CBD has low toxicity.

According to the World Health Organization, across a number of controlled and open-label assessing the potential therapeutic effects of CBD, it is generally well 15 tolerated, with a good safety profile.


Machado Bergamaschi, M., et al., Safety and side effects of cannabidiol, a Cannabis sativa constituent. Current drug safety, 2011. 6(4): p. 237-249

Biochemical and Behavioral Side Effects of Cannabidiol

A meta-review of clinical data regarding CBD use in humans and animals revealed that there were no significant side effects on physiological or biochemical parameters. Similarly, the use of CBD did not cause any behavioral side effects except in cases where highly excessive doses were administered (150 mg/kg of body mass by way of IV or an oral dose of 30mg/kg for 90 days).


Iffland, K. and F. Grotenhermen, An Update on Safety and Side Effects of Cannabidiol: A Review of Clinical Data and Relevant Animal Studies. Cannabis and Cannabinoid Research, 2017. 2(1): p. 139-154.

Adverse Side Effects and Reactions in Humans

A study published in the journal of Current Pharmaceutical Design looked at the effects of THC, CHB and THC + CBD combinations. What they determined, was that CBD alone does not produce the side effects commonly seen or experienced with THC, and that CBD is generally well-tolerated and a strong potential candidate for therapeutic applications.


Martin-Santos, R., et al., Acute effects of a single, oral dose of d9- tetrahydrocannabinol (THC) and cannabidiol (CBD) administration in healthy volunteers. Curr Pharm Des, 2012. 18(32): p. 4966-79.

Interactions with Medication: a likely culprit for side effects

When it comes to CBD and side effects, it is thought that a large percentage of adverse reactions are due mainly to drug interactions for those currently taking either over the counter or prescribed medication.

CAUTION: Never use CBD in combination with other drugs or medications without first speaking with your pharmacist and/or doctor about the potential of interactions or adverse effects.

For example, researchers at Penn State College of Medicine studied known data about CBD and THC and discovered that 139 identified medications can be affected by the use of cannabinoids. 57 of which were found to be altered to the extent that they may become dangerous for the patient, causing serious and sometimes life-threatening interactions.

The Most Dangerous Interactions Were Those Seen With:

  • Certain blood thinners
  • Heart rhythm medications
  • Thyroid medications
  • Seizure medications

Consumer Reported Side Effects of CBD

Side effects reported by consumers are typically mild (if any) and easily manageable.

Side Effects of Cannabidiol Reported by Consumers Include:

  • Dry mouth
  • Stomach discomfort
  • Sedation or drowsiness
  • Reduced reaction time
  • A deeply relaxed state of mind

Not So Fast Says the FDA

Despite approving the first-ever CBD-based drug (Epidiolex) for use in treating specific types of epilepsy, the organization has remained cautious about endorsing the use of CBD for any other purpose.

In this regard, the FDA has taken a stance that is arguably as bit biased given its relationship with cannabis in the past, and the current legislative battle over what is and isn’t legal.

When the World Health Organization (WHO) says CBD is ‘well tolerated’ and ‘generally safe for human consumption’, it makes you wonder why the FDA has been so loud about its potential side effects.

Nevertheless, the following represent the side effects the FDA warns consumers to be cautious about:

  • Liver damage: several studies have linked CBD use to liver damage. However, in the vast majority of cases, the damage was minimal (similar to drinking alcohol)
  • Slower reaction time and sedation: increasing the risk of injury
  • Damage to male fertility/reproductive toxicity
  • Changes in the level of alertness
  • Gastrointestinal distress (decreased appetite and/or diarrhea)
  • Potential for yet unknown side effects
  • Interactions with medications
  • Adulterated or impure products from shady manufacturers



Cannabidiol and Side Effects: the bottom line

Tens of millions of individuals around the world take CBD for a wide range of reasons, most of which revolve around health, wellness and improving quality of life. For centuries cannabis and CBD (the second most abundant cannabinoid in marijuana and the most abundant in hemp) has been consumed, largely without issue.

Although any supplement has the potential for side effects, including those as benign as coffee or aspirin, CBD has been deemed by the WHO to have a good safety profile, and to be generally well tolerated by most people.