One of the first uses of toxins in flies was to genetically ablate specific cells with cell-lethal toxins such as diphtheria toxin (Kunes and Steller, 1991) or ricin (Moffat et al., 1992) . It is also possible to block the neuronal activity of cells without killing them, as with tetanus toxin (TTX), which was used to block synaptic transmission in the nervous system (Allen et al., 1999; Baines et al., 1999; Reddy et al., 1997; Sweeney et al., 1995) and activity-dependent regulation of synaptic size and function (Nakayama et al., 2006) . TTX has been used in a myriad of Drosophila studies to inhibit neurotransmission in various processes, including learning and memory, locomotion and courtship (for a review, see Martin et al., 2002) , circadian rhythms (Johard et al., 2009; Kaneko et al., 2000) , and the serotonin-dependent response to light (Rodriguez Moncalvo and Campos, 2009) . Similarly, application of cholera toxin (CTX), an ADP-ribosylation factor, was used to study the function of the G protein Concertina, which is involved in initiating embryonic gastrulation (Morize et al., 1998) . Similarly, transgenic expression of a UAS-CTX-A construct helped to distinguish which heteromeric G proteins contribute to wing maturation (Katanayeva et al., 2010) . Indeed, these and other toxins, which neutralize or alter the activities of multiple host proteins, can be used to perform a variety of in vivo pharmacological studies to complement classical genetic loss-offunction studies.