According to naturopathic doctor Tracey Beaulne of Naturopathic Family Medicine in Toronto, if you suffer from seasonal allergies, reaching for probiotics, such as acidophilus, should one of your first preventative steps. Beyond the fact that all stomachs can benefit from the boost probiotics lend to digestion and immunity, they can also influence the immune system and potentially correct the root cause of allergic reactions, she says. Aim to take a daily dose of the BB536 strain year-round from food, and follow any course of antibiotics with acidophilus for double the length of time you were taking medication.