Unfortunately some producers do not work hygienically. The result is powder with a high count of various coli-forms, even e-coli. These will give you diarrhea if not worse. In the USA most producers irradiate moringa to kill bacteria and viruses. We prefer hygienic handling throughout the value-chain and do not irradiate. That is why we test produce before we use it.
NOTE that a high dose of Moringa acts as a laxative, especially on an empty stomach (see previous point).