Thank you for your query.
Lactogen contains lactose and will cause diarrhoea
if given to a lactose intolerant child.
Use lactose free formula and a weel balanced diet(soild).The child should gain weight after this.
Do not panic,everything will be fine.
Consult your doctor if the problem persists.
If you have any further queries you are free to consult me.
Hope this answers your query.
Wishing a speedy recovery.
Have a nice day.