Commonly known as saffron, Crocus sativus L and its active components have shown several useful pharmacological effects such as anticonvulsant, antidepressant, anti-inflammatory, antitumor, radical scavenger effects, learning and memory improving effects, etc. There has been an increasing body of data on saffron use in medical databases within the last 20 years. In the current review, the strengths and weaknesses of some of the clinical trials about different pharmacological effects of saffron will be discussed C. sativus extract has been studied in 8 antidepressant clinical trials in comparison to placebo or some antidepressant drugs, in which saffron showed effectiveness as an antidepressant drug. Clinical trials on anti-Alzheimer effect of saffron demonstrated that it was more effective than the placebo, and as effective as donepezil. 2 clinical trials on antipruritic and complexion promoter in skin care effects of saffron both confirmed that saffron was more efficient than the placebo. In another clinical trial, it was proved that in addition to the weight loss treatment, saffron could reduce snacking frequency. Clinical trials conducted on women with premenstrual syndrome showed that saffron could reduce suffering symptoms more than the placebo and similar to standard treatments. Furthermore, additional clinical trials on effects of saffron on erection dysfunction, allergies, cardiovascular and immune system as well as its safety, toxicity and human pharmacokinetics are reviewed herein.