Background: Skin-lightening products are increasingly common in European cities. These products may contain substances that are banned under EU regulations as they can induce adverse effects, including cutaneous and systemic reactions (e.g., mercury, hydroquinone and topical corticosteroids). Objectives: To assess the knowledge, attitudes and practices of women regarding skin-lightening products and to quantify the potentially harmful substances in the products used. Methods: We performed a cross-sectional study among 82 non-Italian women visiting an outpatient facility in Rome, Italy. The women completed a questionnaire on product use, side effects and risk awareness. We performed patch tests among a subgroup of 48 women who presented with contact dermatitis. We also quantified the allergenic and toxic substances in the 14 products reported, using dynamic reaction cell inductively coupled plasma mass spectrometry for metals and high-performance liquid chromatography for hydroquinone and topical corticosteroids. Results: Out of the 82 women, 33 used skin-lightening products; about one fourth of these women were aware of potential risks. Three cosmetic creams and two soaps contained high concentrations of metals (Cr, Ni and Pb); hydroquinone was found in three creams and one oil. The only topical corticosteroid detected was dexamethasone, in one product. More than half of the women in the clinical evaluation had irritant contact dermatitis (i.e., negative response to patch test). Conclusions: Among immigrant women in Rome, the use of skin-lightening products seems to be fairly common, and some of these products contain potentially hazardous substances. Consumers must be informed of the potential risks, and EU regulations must be more strictly enforced.