Crocus sativus L. (saffron) in the treatment of premenstrual syndrome: A double-blind, randomised and placebo-controlled trial 

In a double-blind, placebo-controlled trial, women aged 20-45 years with chronic PMS symptoms (minimum six months) were randomized to receive 30 mg of saffron daily or placebo for two menstrual cycles. Changes were monitored through daily symptom reports and the Hamilton Depression Rating Scale (HDRS). Researchers found that women treated with saffron had a significant decrease in PMS symptoms with improvements in both Daily Symptom scores and the HDRS particularly in the 4th month of supplementation. 

References:

Agha-Hosseini M, Kashani L, Aleyaseen A, et al. Crocus sativus L. (saffron) in the treatment of premenstrual syndrome: a double-blind, randomised and placebo-controlled trial. BJOG. 2008;115(4):515-519. doi:10.1111/j.1471-0528.2007.01652.x https://pubmed.ncbi.nlm.nih.gov/18271889/