Making a nasal spray with toad venom that can relieve depression for two months One dose of a nasal spray containing a psychoactive compound extracted from the venom of a species of toad may help reduce depressive symptoms quickly, researchers have shown in a clinical trial. Of course, these results are preliminary and more research is still needed to use this method as a routine treatment for depression. In the experiment, people suffering from depression were randomly given a dose of nasal spray that contained one of three amounts of 0.3, 8 and 12 mg of the active ingredient. Improvement in depressive symptoms usually began about two days after the session and lasted for at least eight weeks.