To determine: the effectiveness of three anticholinergic medications in reducing drooling in children with developmental disabilities (such as cerebral palsy, intellectual disability, and autism spectrum disorder), the frequency and nature of side effects, and their impact on treatment discontinuation.After prescription of benzhexol hydrochloride, glycopyrrolate, or scopolamine patches at a tertiary saliva control clinic, all carers of 110 consecutive, eligible patients were recruited over a 5-year period. They provided data for 52 weeks, or until drug discontinuation, on compliance, drooling, adverse effects, and reasons for cessation. We evaluated and compared best drooling response, side effects, and drug cessation rates using survival analysis, and the effect of baseline variables on the discontinuation rate using proportional hazards regression.Among 110 participants (71 males, 39 females; mean age 8y 5mo [SD 4y 3mo], range 1y 11mo-18y 11mo), benzhexol, glycopyrrolate, and scopolamine were prescribed 81, 62, and 17 times respectively, with respective response rates of 85%, 75%, and 65%. Poor head control and poor oromotor function were predictive of poor response. Side effects frequently prompted drug cessation in males more than females (hazard ratio 1.8 [95% confidence interval 1.0-3.2], p=0.048). Glycopyrrolate had the fewest side effects.Benzhexol, glycopyrrolate, and scopolamine reduce drooling, but improvement is offset by adverse side effects. Overall, glycopyrrolate performs best.In drooling, glycopyrrolate produced the greatest improvement with fewer side effects compared with benzhexol and scopolamine. Poor head control and poor oromotor function were associated with poor response. Medication side effects were common and often led to treatment discontinuation. Behavioural issues instigated cessation of benzhexol more often in males than females.