My puppy had this off and on for 6-8 months. He’s now a bit over a year and hadn’t had it since. Never treated it. Most likely allergies. He hasn’t had it since April.

Vet said just an irritant. Prescribed eye drops. THANKS!
—OP

Eye infection. Very painful and needs to go to vet as soon as you can

Any vomiting, coughing or other symptoms, or just the eye discharge? It could be a lot of things from your description. At 4 months, she should have received at least 2 rounds of vaccines, correct ?

My 4 month old has red bloodshot eyes and green discharge. Her appetite has decreased the last few days. I have vet appt but wondering if anyone else has experience with these symptoms. Thanks.