Cranberry

Vaccinium macrocarpon · PACs

Snapshot

Indications	Contraindications
Recurrent urinary tract infection^{1, 2} Urinary infection after surgery³ Systolic blood pressure⁴ UTIs in women on SGLT-2 inhibitors⁵ Helicobacter pylori suppression⁶	History of kidney stones⁷ Warfarin therapy⁶ Tacrolimus therapy⁶

Cranberry (Vaccinium macrocarpon) is an evergreen shrub whose fruit is taken as juice, powder, or extract; its proanthocyanidins (PACs) are thought to stop bacteria sticking to the bladder wall⁸. That effect drives its main use, preventing recurrent urinary tract infections (UTIs) as a nonantibiotic strategy⁸. Smaller uses include Helicobacter pylori suppression⁶, glycemic control in diabetes, and blood pressure.

Meta-analyses found cranberry reduced UTI recurrence in otherwise healthy women¹. Per the National Institutes of Health fact sheet, results are inconsistent in long-term-care residents and pregnancy, and it is not recommended to treat an existing infection⁸. In healthy active adults, a 2024 study found four weeks of cranberry extract improved a measure of muscle oxidative capacity; the finding awaits replication⁹. Products listing cranberry come mostly as capsules alongside juice, tablets, softgels, and gummies; see Form comparison.

Cranberry contains oxalate, the component of the most common kidney stones⁶. For warfarin, Memorial Sloan Kettering calls the data mixed and says usage is to be monitored by a healthcare professional⁶.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

51 sources, 42 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources