Hi, Clear watery fluid from one nostril only should be taken seriously unless proved otherwise due to fluid leakage from the brain through bone defect in skull base. This needs special investigations under the care of the skull base surgeon. Spinal injection of a due and then MRI and Fluoroscopy to confirm. If this is so then you need a Special surgery by an ENT Surgeon specialised in such surgeries through endoscopy. If this is not the reason then fluid from allergic sinusitis is a possibility. CT scan of sinuses and nasal endoscopy will confirm the diagnosis and thus allow a specific treatment. Hence consult an ENT SUrgeon asap and go for investigations to get a confirmed diagnosis before starting symptomatic treatment. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. T. Chandrakant, General Surgeon