Are There Side Effects Of Ginseng On A TIA Patient ?

Hi! Two weeks ago my 62 year old husband had a TIA; only symptoms were confusion & loss of short term memory for a few hours. Every test possible was conducted & all came back normal. His total cholesterol is 207 but since he has good blood pressure, not diabetic, not overweight, walks briskly daily, etc. the doctor did not prescribe a statin. The bottom line is that they have no idea what caused it. The only thing different he has been doing is putting a piece of ginseng root in his green tea which he drinks in the afternoon. After the tea he then chews & swallows the root. He has been doing this for the past month. Are there side effects to ginseng? Thank you. Jeanie