Thank you for your query on Healthcare Magic.
I advise you to give exclusive breastfeeding
to your child till the age of 6 months.
The diarrhea may be due to a virus or bacteria due to contamination by giving top feeds with a bottle.
Maintain hydration by giving breastfeeds frequently and by oral rehydration solutions like Pedialyte
You can give probiotic
or saccharomyces after the advise.
The wrong may be in the technique of feeding in giving the top feeds.
Hope I have answered your query.