AbstractAllergic contact dermatitis (ACD) from isothiazolinones has frequently been described in the literature. Following an epidemic of sensitization to methylchloroisothiazolinone/methylisothiazolinone (MCI/MI) in the 1980s, and more recently toMI, the Scientific Committee on Consumer Safety of the European Commission banned their use in leave‐on products, while restricting that in rinse‐off cosmetics. Despite a decreasing prevalence ofACDfromMCI/MIandMI, cases caused by occupational exposure and non‐cosmetic isothiazolinone sources are on the rise. Moreover, sensitization to newer and lesser known isothiazolinones has been reported. This paper reviews the epidemiology of contact allergy to different isothiazolinones, clinical presentation of isothiazolinone‐inducedACD, most relevant sensitization sources and potential cross‐reactions between isothiazolinone derivatives. It also provides an update on recent legislative measures.