It's an article I translated it from Thai to English.

**I wanna know the correction of this in terms of grammar, using vocabularies and etc..

All antioxidants may not be good
The A study on guinea pigs showed that some antioxidants were not good for health in terms of resisting cancer, a Taiwanese researcher said reported ("said" is OK, "reported" might be better). Kuan-Chou Chen, the researcher from Taipei Medical University of Shuan-Ho Hospital, informed the USFDA and other health associations in currently evaluating the safety of antioxidants which were from a new plant since it was found from that the result of the experiment on the guinea pigs was that there were two kinds of substances which made cancer even worse. These two substances were used in making herbs for treatment and for supplementary food.
This research found that the two kinds of antioxidants which were found in this plant, called quercetin and ferulic acid, stimulated to cause the growth of kidney cancer in the guinea pigs which had diabetes.
“Our research found that quercetin stimulated to cause the growth of kidney cancer even if it was not directly. Some scientists believed that quercetin shouldn’t be used by healthy people to protect against disease for healthy people until it was surely proven not to be a the cause of cancer,” Chen said. The researchers also said that the quercetin substance could be found in onions and black tea; as for ferulic acid, it could be found in corn, tomatoes and rice bran.
Having Taking supplementary food or any type of antioxidants should only be in done on a doctor’s advice; you shouldn’t buy and have take them by yourself.

***Thank you in advance for correcting my work :)