CBD has extremely low toxicity and no adverse effects with short-term use. On rare occasions, mild to moderate adverse effects have been shown, with long-term use. The most common (but still very rare) dose-related side effects are sleepiness and sedation. These are observed in early treatment and are likely to diminish over time. These adverse effects can impair the ability to operate machinery or drive.
Extreme caution is required when CBD is co-administered with benzodiazepines, opioids, and other CNS depressants. Such combinations may result in severe respiratory depression.
Although rare, users experiencing discomfort even after a relatively low dose intake of CBD may be allergic to cannabidiol itself or another ingredient in the formulation taken, for example (sesame oil). If this is the case, they should immediately stop its administration and seek medical assistance, if necessary.