Does Lexapro diarrhea last for a while or how can I help it?

Lexapro is an excellent antidepressant/anxiolytic but diarrhea is an unfortunate side effect for some people:
"Very common (10% or more of users): Nausea (up to 18.3%), diarrhea (up to 14%)"
It usually resolves within the first week or two... any longer and you should get professional advice from your doctor. She/he may prescribe an antidiarrheal medication or temporarily adjust your dosage until your metabolism adjusts to the drug.
https://www.drugs.com/article/drug-side-effects.html#sfx-list
Meanwhile, be sure to drink plenty of water or an electrolyte solution to maintain your hydration.

Thats pretty typical in my case when I took it. Your body is adjusting . I took anti-diarrhea med for awhile. An a probiotic. After month it started backing off. But it made me very lethargic an sleepy an I ate all time. I gained 13 lbs in a month an half. I was only on 10mg. It wasnt helping mentally. It is usually is for anxiety but can be given for depression. I guess I didnt take long enough or needed to up it. Goodluck.