Definition of Fruit of poisonous tree doctrine
Evidence which is spawned by or directly derived from an illegal search or illegal interrogation is generally inadmissible against the defendant because of its original taint, though knowledge of facts gained independently of the original and tainted search is admissible. Wong Sun v. U. S., 371 U.S. 471, 83 S.Ct. 407, 9 L.Ed.2d 441. This doctrine is to the effect that an unlawful search taints not only evidence obtained at the search, but facts discovered by process initiated by the unlawful search. This doctrine is generally applied to cases involving searches in violation of the Fourth Amendment to the Constitution right against unlawful searches and seizures, but it can be applied to searches in violation of a statutory right. Duncan v. State, 278 Ala. 145, 176 So.2d 840, 865. See Exclusionary rule.
That's the definition of Fruit of poisonous tree doctrine in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.