Capsaicin is an active ingredient in hot peppers (genus Capsicum, Solanaceae) with analgesic properties. Since its discovery, it has been used as a homeopathic remedy to treat pain. Systematic reviews of the scientific literature confirm that capsaicin is useful in the treatment of various chronic painful conditions. Recent research indicates the great potential of capsaicin for the systemic treatment of many other diseases and conditions, such as obesity, diabetes or metabolic syndrome, but there is still insufficient scientific evidence to justify its use. However, capsaicin preparations are often used, although more clinical studies are needed to evaluate the effects and possible side effects of capsaicin use for certain indications. This paper contributes to the understanding of the mechanism of action, indications and potential adverse effects of capsaicin, which ultimately facilitates the determination of the suitability of capsaicin preparations in pharmaceutical practice. The paper concludes that the use of capsaicin products is justified in the prevention of overweight and pain therapy while there is still insufficient evidence for the use of capsaicin as an antitumor agent and in the treatment of gastrointestinal diseases. Also, when advising patients on capsaicin preparations, it is necessary to warn the patient of clinically significant side effects and other limitations of use.