Allergic asthma is complex inflammatory airway disorder caused by genetic and environmental factors. Sulfamethoxazole, a sulfonamide, is the cause of drug rash with eosinophilia and systemic symptoms syndrome. Parasites infection also related with eosinophilia and allergic diseases. In the present study, we investigated the modulating effects of parasitic derivative and sulfamethoxazole (SMX) on allergic airway inflammation in the ovalbumin (OVA)-induced murine asthma model. Histopathological changes, cytokine secretion, and total and allergen-specific IgE were investigated. BALB/c mice were treated with Ascaris suum extract or SMX for 4 weeks before sensitized and challenged to ovalbumin. Pre-treatment of Ascaris suum extract decreased allergic inflammation in lung tissue and IL-4, total IgE, and OVA-specific IgE levels in bronchoalveolar lavage fluid. However, pre-treatment of SMX did not show any effects on allergic airway inflammation. These results indicate that parasitic infection has protective effects on allergic asthma, but the sulfamamides may not relate with allergic asthma.