Anticholinergic Toxicity: This condition is characterized by symptoms such as dry mouth (cotton mouth), blurred vision, nausea, vomiting, and can be caused by various medications (e.g., antihistamines, antipsychotics, and certain antidepressants) or substances (e.g., jimsonweed). The combination of these specific symptoms points strongly towards an anticholinergic syndrome.

Food Poisoning: Symptoms like nausea, vomiting, and potentially blurred vision (if the toxin affects the nervous system) could be seen in food poisoning. However, cotton mouth is less commonly associated directly with food poisoning unless it leads to significant dehydration.
Viral Gastroenteritis: While primarily causing gastrointestinal symptoms like nausea and vomiting, severe cases can lead to dehydration, which might cause dry mouth. Blurred vision could be a result of dehydration or, less commonly, a direct effect of the virus.
Medication Side Effects: Various medications can cause these symptoms as side effects, including those that affect the gastrointestinal system, the eyes, or have anticholinergic properties.

Botulism: A potentially life-threatening condition caused by a toxin that can lead to blurred vision, nausea, vomiting, and dry mouth among other symptoms. Early diagnosis is crucial for effective treatment.
Organophosphate Poisoning: Exposure to organophosphates (found in some pesticides) can cause a range of symptoms including nausea, vomiting, blurred vision, and dry mouth due to its anticholinesterase activity. Prompt recognition and treatment are vital.
Stroke or Transient Ischemic Attack (TIA): Although less likely to present with this exact combination of symptoms, a stroke or TIA can cause sudden onset of blurred vision, nausea, and vomiting. It's crucial to consider and rule out these conditions due to their severe implications.

Pilocarpine or Cholinergic Toxicity (Reverse of Anticholinergic): While less likely, excessive cholinergic activity can cause symptoms that might seem counterintuitive, such as increased salivation (which could theoretically lead to a sensation opposite of cotton mouth), nausea, vomiting, and potentially blurred vision due to miosis (pupil constriction).
Certain Neurological Disorders: Rare conditions affecting the brain or nervous system could potentially cause this combination of symptoms, though they would be less common and might be accompanied by other neurological signs.