| Rationale | Controlled studies | |
| vs lactulose | vs placebo | |
| Ammonia hypothesis | ||
| Decrease in ammoniagenic substrates | ||
| Enemas with lactulose | + | |
| Restriction of dietary protein intake | ? | |
| Inhibition of ammonia production | ||
| Antibiotics | ||
| Neomycin, paromomycin, metronidazole | = | ND |
| Rifaximin | = | + |
| Vancomycin | =/+ | ND |
| Disaccharides | ||
| Lactulose | ? | |
| Lactitol | = | ND |
| Lactose in lactase deficiency | + | |
| Modification of colonic flora | ||
| Lactobacillus SF 68 | = | ND |
| Correction of hypokalemia | ND | ND |
| Metabolic ammonia removal | ||
| Ornithine-aspartate | + | |
| Benzoate | = | ND |
| False neurotransmitter hypothesis | ||
| Branched chain amino acid supplementation | ||
| Modified amino acid solutions (FO80 type) | = | ± |
| "COMA" solutions | ND | ND |
| Dietary BCAA supplementation | + | |
| Increased dopamine | ||
| L-DOPA, bromocriptine | - | |
| GABA hypothesis | ||
| Flumazenil | + | |
| Other | ||
| Zinc | ± | |
