A more thorough explanation:

Definition: Fruit of the poisonous tree is a legal doctrine that says evidence obtained illegally cannot be used in court. This includes any evidence that was found as a result of the illegal activity. The term "fruit of the poisonous tree" means that if the original evidence is tainted, then anything that comes from it is also tainted and cannot be used in court.

For example, if the police illegally search someone's home and find drugs, any evidence found as a result of that search, such as a confession or other evidence, would also be inadmissible in court.

There are some exceptions to this rule. Evidence may still be admissible if it was discovered from a source independent of the illegal activity, if its discovery was inevitable, or if it was found as a result of excludable, voluntary testimony from the defendant. Additionally, if the primary evidence was obtained illegally but is admissible under the good faith exception, any derivatives or "fruit" of that evidence may also be admissible.

Overall, the fruit of the poisonous tree doctrine is meant to discourage law enforcement from using illegal methods to obtain evidence and to protect the rights of individuals from unlawful searches and seizures.