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Forrest Classification

Dr. Shannon Melissa Chan

Prince of Wales Hospital, The Chinese University of Hong Kong

Forrest Classification

The Forrest Classification was first described in 1974 by J.A. Forrest et al. in TheLancet1. This classification is a widely used classification of ulcer-related upper gastrointestinal bleeding. It was initially developed to unify the description of ulcer bleeding for better communication amongst endoscopists. However, the Forrest Classification is now used as a tool to identify patients who are at an increased risk for bleeding, rebleeding and mortality2–4.

Forrest Classification
Acute haemorrhage
Forrest Ia
Forrest Ib

Active spurter
Active oozing
Signs of recent haemorrhage
Forrest IIa
Forrest IIb
Forrest IIc

Non-bleeding visible vessel
Adherent clot
Flat pigmented haematin on ulcer base
Lesions without active bleeding
Forrest III

Clean-based ulcer

Example illustrations

Figure 1. Forrest Ia gastric ulcer with an active spurter

Figure 2a. Forrest Ib ulcer with active oozing
Figure 2b. Forrest Ib ulcer with active oozing

Figure 2c (i). Forrest Ib ulcer at the gastrojejunal anastomosis, with visible vessel and active oozing.

Figure 2c (ii). The same ulcer as above, but after an injection of adrenaline. This shows a visible vessel at the anastomotic ulcer.
Figure 3a. Forrest IIa ulcer with a visible vessel
Figure 3b(i). Forrest IIb ulcer at incisura. With ulcers with an adherent clot, it is important that the clot must be removed by vigorous and meticulous flushing in order to reveal underlying visible vessels.
Figure 3b(ii). The same ulcer as above, but after the clot was removed. It revealed an underlying visible vessel.
Figure 4a. Forrest IIb ulcer with an adherent clot

Figure 4b. Forrest IIb ulcer with an adherent clot
Figure 5. Forrest IIc ulcer with a pigmented spot

Figure 6a. Forrest III ulcer at antrum with clean base
Figure 6b. Forrest III ulcer at anterior wall of D1/2 with clean base


  1. Forrest, JA.; Finlayson, ND.; Shearman, DJ. (Aug 1974). ‘Endoscopy in gastrointestinal bleeding’. Lancet2 (7877): 394–7.
  2. Rockall, TA, Logan, RF, Devlin, HB et al. ‘Risk assessment after acute upper gastrointestinal haemorrhage’. Gut 1996; 38: 316–21.
  3. Guglielmi A, Ruzzenente, A, Sandri, M et al. ‘Risk assessment and prediction of rebleeding in bleeding gastroduodenal ulcer’. Endoscopy 2002; 34: 778–86.

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