What is it?
Cranberry fruit is nowadays made into juice/pills to help prevent urine tract infection. It also contains salicylic acid like many other vegetables which prevents blood clots, reduce swelling and have some anti-tumor effects.
Cranberry has been scientifically proven that it can prevent urinary tract infection by preventing bacteria to stick to cells that line urinary tract and preventing the bacteria to multiply. It does not work on the bacteria that had stuck on the cells. Hence it is more for preventing urinary tract infection rather than treating it.
More scientific and evidence based studies is required to testify some of the claimed benefits of cranberry such as treating diabetes, benign prostate hypertrophy, helps skin healing, chronic fatigue syndrome and cancer. Currently there are no sufficient evidence to prove these claims.
Possible side effects
It is generally very safe to take cranberry, even in children, lactating and pregnant women. However when you take too much of it, some may have stomach upset and diarrhea. Also if you drink more than 1 liter over a long period of time may increase the risk of developing kidney stones.
As cranberry contains salicylic acid so for people who are allergic to aspirin, they should avoid it.
Patients with kidney stones should avoid cranberry as it increases the chance of kidney stones formation. Kidney stones is made up of oxalate and calcium and cranberry can boost the oxalate level hence increases the risk of stone formation.
Please follow the instructions on product label and if in doubt consult your doctor first.