My Hoyin had s26 from birth to 3 months.
As he was constipated, we changed him to a local formula Karicare.
He gained quite well when he was on s26.
He is still OK now (75%).
I agree with Paulina that fat bbs are good as they lose so much when they are sick.
My Hoyin had a fever last week and he drank less than 5 oz of milk each day for 3 days.