Patients suffering from urinary incontinence are still nowadays mostly treated with oxybutynin. Using ants as models, we found that this drug decreased their food consumption, orientation ability, tactile perception, cognition and memory, induced restlessness and stress, impacted their social relationships and leaded to dependence. No adaptation occurred to these side effects. The action of oxybutynin quickly vanished in 10 hours. Most of these side effects corresponded to those observed in humans (on whom effects on food consumption, activity, cognition and anxiousness can be observed), and some others were observed in ants (impact on social relationships, dependence on the drug and absence of adaptation to its side effects). Ants appear thus to be valuable models for revealing side effects of a drug. On the basis of our results and of those reported in the literature, it can be concluded that patients treated with oxybutynin should be carefully monitored as for their risk of developing adverse effects, even unexpected ones. Novel, safer medicines, presenting a better balance between efficacy and safety should be researched.