Is it forbidden to consume pills of unknown origin that make the user bold and eloquent in speech?

It is not possible to rule on these pills without knowing their true nature and effect, and this matter is best left to specialized doctors. If the doctors state that they have no effect other than what is mentioned in the question, then there is no harm in taking them. However, if they contain anything that necessitates prohibition, such as causing intoxication or harm, then it is not permissible to take them.