Sorry to hear that your baby is having frequent watery green stools recently.
If the consistency is more watery with increased frequency without any recent change in feeding or addition of new medication, the highest suspicion is risk of diarrhoea infection
Next Steps
Make sure he is feeding more than usual to make up for looses in stools
If he gets lethargic/reduced urine nappies/of large diarrhoea frequency is more than you can feed him- seek medical help
Check for fever ( temp over 99.5F)
Consider getting stool routine and culture test to look for infection- if that is case one can consider antibiotic
Health Tips
If there is fever, blood in stool or unwell child- one may need earlier doctor review to decide if antibiotic is needed early