My ds 3.8 years has become lactose intolerant again! This has been happening on and off for the past year, the gp said that he has a sensitive tummy and if he gets a bug can not tolerate dairy. This has happened at least 5 times in the past 12 months and each time we take him off dairy for about a week and he soon starts to get better. I took him to get weighed a few weeks ago as he has always been a small child and he had only gained 1kg in 14 months. Has anyone else any experience of this as I am starting to worry that he is not gaining weight due to the lactose intolerance. Any advice welcome, thanks.