Ask Dr. Litinas is a column that publishes twice monthly as part of The MichiGanja Report—our free, weekly newsletter about all things marijuana. Click here to sign up.
MICHIGAN—Cannabis is often discussed in terms of benefits—like pain relief, euphoria,improved sleep, reduced anxiety, and better quality of life.
But like any biologically active substance, cannabis can also produce side effects. Most are mild and manageable. Some are dose-dependent. And a few—like Cannabis Hyperemesis Syndrome—are rare, can be severe, and are important for Michiganders to understand.
Knowing there can be side effects from cannabis consumption doesn’t make it less useful. It makes it safer and more effective. When consumers understand side effects, they can adjust dosing, choose the right products, and have more informed conversations with healthcare providers.
This week’s column is meant to do exactly that: help Michiganders understand the most common cannabis side effects, recognize less common but more serious reactions, and use cannabis with greater confidence and intention.
Why do side effects happen?
Cannabis interacts with the endocannabinoid system, a signaling network involved in biological processes that control things like pain, mood, appetite, blood pressure, immune function, and cognition. THC, CBD, and other cannabinoids influence this system in different ways.
Those effects vary from person to person. And understanding this context helps explain why many side effects are predictable—and preventable.
Side effects usually arise from:
- Dose (too much, too fast)
- Product choice (THC-dominant vs. balanced)
- Route of administration (oral vs. inhaled)
- Individual sensitivity
- Interactions with other medications
What are some of the most common cannabis side effects?
Drowsiness and fatigue: Feeling sleepy is one of the most common effects of cannabis, especially products containing THC or higher doses of CBD. This effect can be helpful for nighttime use or sleep, but problematic during the day. Starting with lower doses and reserving THC-containing products for evening use often reduces unwanted fatigue.
Dizziness or lightheadedness: Dizziness may occur, particularly when standing up quickly or if you are new to cannabis use. Cannabis can cause temporary changes in blood pressure, leading to a sensation similar to orthostatic hypotension and/or instability. Careful use is important especially in elderly consumers as the danger of falls can be high. Hydration, slow position changes, and lower starting doses help minimize this effect.
Dry mouth (and dry eyes): Often called “cotton mouth,” this occurs because cannabinoids reduce salivary secretion. While uncomfortable, it’s generally harmless. Staying hydrated, chewing sugar-free gum, or using lozenges usually helps.
Anxiety or restlessness: Ironically, cannabis—especially higher doses of THC—can cause anxiety in some people. This is one of the clearest examples of why dose matters. Anxiety is far more common when THC is introduced too quickly or at too high a dose. Lower doses, balanced THC:CBD products, and slower titration significantly reduce this risk.
Nausea: Cannabis is often used to treat nausea, but in some individuals—particularly with higher THC doses—it can initially worsen it. If nausea occurs, reducing the dose or switching to a different formulation often resolves the issue.
Cognitive effects: Cannabis can affect attention, short-term memory, and reaction time—again, most commonly with THC. These effects are usually temporary and dose-dependent. This is why driving, operating machinery, or performing complex tasks should be avoided until you know how cannabis affects you.
Drug-to-drug Interactions: Cannabinoids are metabolized by liver enzymes in the CYP450 system. This means cannabis can change how certain medications are processed in the body. Potential interactions may occur with blood thinners, anti-seizure medications, certain antidepressants, sedatives, and other drugs. This doesn’t mean cannabis can’t be used—but it does mean your healthcare provider should be aware of your full medication list.
Airway irritation from smoking: Smoking cannabis can irritate the airways, leading to coughing, throat irritation, or bronchial discomfort. For patients with asthma, COPD, or other lung conditions, non-inhaled options—such as tinctures, capsules, or edibles—are often safer alternatives. Vaporization may reduce irritation compared to smoking, but oral (or swallowed) routes remain the least irritating to the lungs. Overall avoid inhalation if possible to mitigate any airway irritation.
What are some uncommon cannabis side effects?
Blood pressure changes: Cannabis can temporarily lower blood pressure or, in some cases, cause fluctuations that lead to dizziness or fainting. People with cardiovascular conditions should start at very low doses and be monitored closely.
Heart rhythm disturbances (arrhythmias): In rare cases, cannabis—particularly THC—may provoke heart rhythm changes, especially in individuals with underlying heart disease or arrhythmia risk. This is why cautious dosing and medical guidance are important for patients with known cardiac conditions.
Cannabis Hyperemesis Syndrome (CHS): CHS is a rare condition seen in some long-term, heavy cannabis users. It presents as recurrent, severe nausea and vomiting and often improves with cessation of cannabis use. Sometimes, it even involves “scromiting,” a combination of screaming while vomiting due to intense pain. While uncommon, awareness is important—especially if persistent vomiting occurs in someone using cannabis regularly.
How can I reduce the risk of side effects?
Most cannabis side effects can be minimized by following a few foundational principles:
- Start low and go slow.
- Increase doses gradually.
- Match the product to your goal.
- Use THC cautiously, especially at first.
- Avoid mixing cannabis with alcohol.
- Communicate with your healthcare provider.
- Go to the emergency room if necessary.
These steps allow you to learn how cannabis affects your body before pushing doses higher.
The bottom line
Cannabis is a powerful, biologically active medicinal plant. Most side effects are mild, predictable, and dose-dependent. A smaller number are serious and largely avoidable with education and intentional use. When patients and consumers are informed, they can adjust, adapt, and use cannabis in a way that supports their health, safety, and quality of life.
This content is for education, not medical advice. Talk to your doctor before making any health decisions—especially when it comes to cannabis. Products are only for adults ages 21 and up.
READ MORE: What science says about how Michiganders should use cannabis for pain
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