Acetylcholinesterase inhibition by organophosphorus insecticides can cause acute parasympathetic system dysfunction, muscle weakness, seizures, coma, and respiratory failure. Prognosis depends on the dose and relative toxicity of the specific compound, as well as pharmacokinetic factors.We conducted a systematic overview, aiming to answer the following clinical question: What are the effects of oxime treatment for acute organophosphorus insecticide poisoning? We searched: Medline, Embase, The Cochrane Library, and other important databases up to October 2014 (Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview).At this update, searching of electronic databases retrieved 25 studies. After deduplication and removal of conference abstracts, 14 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of eight studies and the further review of six full publications. Of the six full articles evaluated, one update of a systematic review previously included in this review was added. We performed a GRADE evaluation for six PICO combinations.In this systematic overview, we categorised the efficacy for two comparisons based on information about the effectiveness and safety of oximes versus placebo or no oximes and oximes versus each other.