Gastrointestinal tract dose-response data

An acute oral MRL for formaldehyde was not derived because data describing dose-response relationships for gastrointestinal tract irritation in humans or animals after acute oral exposure are lacking. The reports of gastrointestinal effects and symptoms in humans who ingested single large doses (>200 mg/kg) of formaldehyde (Burkhart et al. 1990 Eells et al. 1981 Kochhar et al. 1986), coupled... 

Recent data indicate that PTX-2 is much less toxic orally than by intraperitoneal injection. Although early studies suggested that PTX-2 was orally toxic, these data are questionable because of the absence of a dose response-relationship. In a later study, no deaths or other changes were recorded with PTX-2 at a dose of 5000 [tg/kg. The low oral toxicity of PTX-2 may reflect poor absorption from the gastrointestinal tract or conversion to a less toxic material, such as PTX-2 seco acid, in the gut [26]. 

An early symptom of lead poisoning is colic, warning that more serious effects may occur with continued and prolonged exposure. Colic is commonly noticed in industrial exposure cases and in lead poisoning of infants and young children. Although there is extensive documentation in the literature, data are insufficient to establish a dose-response relationship for the effect of lead on the gastrointestinal tract [73]. 

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