Just because a product contains natural ingredients it still has the potential to cause irritation and allergic reactions. Products with rosemary, tea tree oil, and chamomile are just some of the natural agents that can trigger allergic contact dermatitis. In some cases, symptoms, such as a rash, do not appear immediately after exposure, but rather a day or two could pass before any signs are noticed. Especially for sensitive skin types, it is wise to test a new product by applying a very small amount first to make sure that it is safe for your skin.