Okada 1985.

Methods	Double‐blind, comparative study.
Participants	N=62; Geographic region: Japan Mean age: not reported Discontinuations/Not available to follow‐up: none reported
Interventions	PPC (amino acid preparation) (n=32) vs. 2 Pollen extracts (n=30). Study duration: 4 weeks
Outcomes	Subjective symptoms; changes in prostate (tenderness, swelling, and sclerotic change); adverse events
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment (selection bias)	Unclear risk	B ‐ Unclear