Unilateral unresponsive pupil dilation results from various neurological and ocular disorders. Third nerve palsy, Adie’s pupil, traumatic mydriasis, and pharmacologic mydriasisare the ocular disorders resulting in unilateral mydriasis. Unilateral mydriasis without sistemic disorder is a topical side effect of Datura inoxia and Brugmasia plants. Datura toxicity related symptoms ocur within sixty minutes after ingestion and usually last 24 to 48 hours. A case was reported of a pharmacological mydriasis caused by exposure to Datura inoxia plant products. This pharmacological mydriasis is defined as “Gardener’s pupil”. Mydriatic effect is caused by toxic plants including anticholinergic substances such as scopolamine, hyscyamine and atropine. Suspicion of an accidental intoxication should be considered if the unilateral mydriasis is detected in patients without evidence of other neurological symptoms. A well conducted history and a simple topical pilocarpine test excludes the necessity of redundant expensive neuro-imagingtechniques.