Hi, we had a very similar problem with our puppy (now 5 months old). We got him from a breeder who we thought was reputable but things have turned nasty and to cut a long story short it may now go to court.

Anyway, it could be caused by so many different things. Is Lemon wormed? This can cause runny/soft poo with bright red blood in it - from our own experience. We have used Panacur 10% liquid and wormed every 2 weeks for 2 months to make sure all eggs and larvae are also killed.

It could be a sensitivity to something not agreeing with him in his food although I have heard from someone I do trust that puppies rarely have true allergies as they are too young to have developed one. It is definitely the case you don't want to change foods too quickly or too often with young pups - but equally their poo should be firm and it's not good for them to be constantly having diarrhea.

Lastly, it could be caused by a virus or bacterial infection. This will only be cleared up with medicine from the vets and can be tested by a fecal sample test.

I took our puppy to the vets and was told to worm, starting immediately, and switch him onto a sensitive food (avoiding chicken and cereals/wheat etc as these are common allergens). In our case we were told he had been wormed up to date hence why we didn't think it could be worms - but he obviously wasn't and had huge ones This may be the case with you?

We slowly switched him onto Arden Grange Sensitive (white fish and potato) and along with the worming his poos started to return to normal within a week.

If I were you I would take Lemon to the vets for a check over but maybe try worming and a sensitive food. We were told that if things didn't improve in a few weeks then they would send off a fecal sample for testing - luckily we didn't need to do this.

Is Lemon lively and his normal playful self or is he lethargic? Ours was normal in himself but just diarrhea when he did go to the toilet. I think virus's and bacterial infections tend to cause other symptoms as well (such as vomitting) and for the puppy to be out-of-sorts, lethargic etc.

Hope this has helped? Our puppy had soft (cow-pat!) poos for about 4-5 weeks after us collecting him at 12 weeks until we managed to sort out the problem with 2-weekly wormings and a sensitive food.

Just a note: he may not be sensitive to a normal dry food but any worms and/or infection will sensitise and irritate the gut so something highly digestible and easy on the stomach/gut may help him get through this phase without feeling too poorly.