By per-oral intubation of the stomach, four groups of rats (n = 22) received ASA 64 mg/kg, alone or with taurodeoxycholic acid (TDC, 5 mM), DGL (2000 mg/kg) or TDC plus DGL. At four hours the severity of bleeding was assessed by a lesion scoring system and expressed as medians and quartiles. In a separate study two groups of rats (n = 7) received ASA (128 mg/kg) or ASA plus DGL (2000 mg/kg) and salicylate levels measured in serial tail blood samples at 20, 40, 60 and 80 minutes. Lesion scores were increased from 6(3;10) with ASA alone to 12(5;16) by TDC (p less than 0.05) and reduced by DGL to 1(0;3.5) for ASA alone and 3.5(0;6) for ASA plus TDC (p less than 0.0005 in both cases). In the second study a slight reduction of ASA absorption was found only at 20 minutes with a median level of 0.9 mmol/l for the DGL treated rats and 1.2 mmol/l for the ASA alone group (p less than 0.05). No differences were found at the other times. We have also demonstrated that although DGL diminished ASA (128 mg/kg)-induced gastric mucosal damage from 17(12;25) to 8(3;14) (p less than 0.005) when the two were given together it did not do so significantly when DGL was given before ASA--15(20;22). Intraperitoneal DGL reduced lesion scores from ASA (128 mg/kg) from 14(11;24) to 7(1;19) (p less than 0.03), thus indicating a systemic as well as a local effect of the drug.  
Deglycyrrhizinised liquorice (DGL) stimulated proliferation in the forestomach of the rat but did not stimulate and possibly even inhibited proliferation in the glandular part. DGL increased the number of fundus glands in which labelled mucus secreting cells occur as well as the total number of labelled mucus cells per gland. The mechanism of action proposed for DGL is that DGL stimulates and/or accelerates the differentiation to glandular cells as well as mucus formation and secretion. The accelerated proliferation observed in the forestomach is ascribed to an improved environment in the stomach as a consequence of the enhanced mucus secretion under the influence of DGL
Gastric mucosal damage induced by giving 60 mg aspirin orally to rats was reduced by simultaneous administration of 100-500 mg deglycyrrhizinated liquorice. Human faecal blood loss induced by 975 mg aspirin orally three times a day was less when 350 mg deglycyrrhizinated liquorice was given with each dose of aspirin.
Studies on the protective effect of deglycyrrhinised liquorice against aspirin (ASA) and ASA plus bile acid-induced gastric mucosal damage, and ASA absorption in rats, Russell RI, Morgan RJ, Nelson LM. Eur J Pharmacol. 1981 Jun