Pac Health Dialog. 2009 Nov;15(2):21-32.
A double-blind clinical safety study of noni fruit juice.
West BJ, Jensen CJ, White LD, Palu AK, Westendorf J.

A 28-day, double-blind clinical trial of Tahitian Noni Juice with ninety-six healthy adult volunteers revealed that drinking up to 750 mL per day is safe.  TNJ ingestion did not cause side effects and did not result in adverse changes to hematology, biochemistry, urinalysis, or electrocardiogram measurements.  It did not cause negative changes to vital signs.  Further, those who drank TNJ experienced 20 to 50% fewer total adverse events than those in the placebo group. (original abstract available at https://www.ncbi.nlm.nih.gov/pubmed/20443518).