This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Forensic Medicine
A 10 year old boy consumes stain remover. He presented with 'coffee-coloured' vomiting and restlessness. Most likely diagnosis: September 2012 
Select and explain. 
A. Oxalic acid, B. Diluted HC1, C. Kerosene, D. Carbolic acid
A: Oxalic acid
Answer: A: Oxalic acid 
Explanation: Ans. A i.e. Oxalic acid The vomit in oxalic acid poisoning has a coffee ground appearance because the oxalic acid badly corrodes the stomach walls. There may be bloody vomiting for the same reason.