Hello Common causes of runny nose in early infancy includes viral infection or due to allergy. Viral infection may cause epithelial damage leading to secondary infection of bacteria. Some physician prescribe antibiotics to be on safer side while some avoid this and uses only when there is any suggestive feature of bacterial infection or diagnosis is not clear. You can give sporidex, t-minic drops as these formulations are made for infants and side effects are very few. Nasivion mini drop is used to clear nasal obstruction. Don t use any home remedy as below 6 months child should be exclusively breast fed and giving other thing may cause infection in child. Keep the child s atmosphere free from dust, smoke and other allergens. With regards