Now I am sending you a very interesting article for its use in psychiatry.c [chronic schizophrenia]

Triphala [an Indian herbaL-fruit formula]I often used for all kinds of “gastro-problems” and also if people get chemotherapeutic drugs as it may highly protect the interlines in these cases]

Phytother Res 2021 Nov 23

It is available in capsules and in powder, sometimes out of stock.

For example:
Starwest Botanicals, Organic Triphala PWD (Trifala) Blend, 1 lb (453.6 g)
Product ID: STR-09080Weight: 0.56 kg₪45.16 kosher which contains black myrobalan =Terminalia chebula