Hello;
welcome to HeathcareMagic
If it is a streak of blood mixed with stools or you pass few drops then the bleeding is probably from piles.Normally milk or milk products do not cause any problem but if you are feeling constipated then if you strain for stools then you may bleed during passing stools.As for the remedy please get examined by a doctor and he will treat you.
Thanks

Welcome to HCM,
Your observation that milk and milk products(except curd) causing bleeding per rectum,the next day points to a very important aspect of milk.Milk usually considered the safest and healthy food can in some people cause constipation because of opoid like peptides present in it.Constipation in effect can cause difficulty in evacuation as a result of which straining is imminent which can at times rupture the lower anal mucosa causing fissures.This can present as blood along with stools which is what you have been presenting with.
The best way to treat this is avoid dairy products especially at night except curd(which has probiotics in it),you can have good amount of salads at night which helps in a good bulk formation and thus easing evacuation of bowels.
Laxatives are very rarely needed in such cases and try to avoid unless dietary methods fail.
Hope your query has been answered well.
Have a healthy life