Marshall’s Flea & Tick Spray is a part of the Marshall flea and tick control system, the only complete ferret flea control system on the market. Flea & Tick Spray contains Resmethrin, which results in a high mortality rate for both fleas and ticks. The gentle, non-drying and non-toxic formula is ideal for use between shampooings, and can be sprayed directly on your ferret and his bedding. 8 oz.