There is disclosed herein a composition for treating gastrointestinal or neurological disorders, constipation, functional constipation, irritable bowel syndrome, diverticulitis, travelers' diarrhea, chronic idiopathic nausea, IBD-associated constipation and diarrhea, pseudo-obstruction, diabetic gastroparesis, cyclic vomiting, reflux oesophagitis, autism enteropathy, flatulence, halitosis, chronic fatigue, bloating, proctalgia fugax, Parkinson's disease, MS, Alzheimer's Disease, Motor Neurone Disease or autism, the composition comprising: (i) at least two anti-Clostridial agents selected from the group consisting of: vancomycin, vancomycin derivatives, a multi-valent polymer of vancomycin, aminoglycosides, nitroimidazoles, ansamysins, nifuroxazide, colchicine, prucalopride, prokinetic agent and 5-aminosalicylic acid; or (ii) at least one anti-Clostridial agent selected from the above combined with an opioid blocking agent. There is also disclosed herein a method of treating various gastrointestinal or neurological disorders, constipation, functional constipation, irritable bowel syndrome, diverticulitis, travelers' diarrhea, chronic idiopathic nausea, IBD-associated constipation and diarrhea, pseudo-obstruction, diabetic gastroparesis, cyclic vomiting, reflux oesophagitis, autism enteropathy, flatulence, halitosis, chronic fatigue, bloating, proctalgia fugax, Parkinson's disease, MS, Alzheimer's Disease, Motor Neurone Disease or autism, the method comprising administering orally, via enema or by suppository: (i) a composition of the invention; (ii) at least two anti-Clostridial agents selected from the group consisting of: vancomycin, vancomycin derivatives, a multi-valent polymer of vancomycin, aminoglycosides, nitroimidazoles, ansamysins, nifuroxazide, colchicine, prucalopride, prokinetic agent and 5-aminosalicylic acid; or (iii) at least one anti-Clostridial agent selected from the above and an opioid blocking agent to a patient in need of such treatment.