The LD50 test is helpful for assessing acute toxicity but it fails to capture the complexity of chemical toxicity, especially chronic health effects like cancer, reproductive toxicity, & ecological impacts. For example - LD50:

• DDT (113 mg/kg),

• Caffeine (150 mg/kg - as low a 57 mg/kg reported),

Yes, you can say both are toxic [in fact both are in same Class 3 (toxic)], but would you really extend this comparison to other important toxicological endpoints. A simple message here:

please don’t use the LD50 of a chemical as a basis of comparison between molecules when more complex endpoints are important in regards to human health and the environment.

An additional explaination:

The LD50 test is inadequate for assessing cancer, developmental and reproductive toxicity, or ecotoxicology because it only measures acute toxicity based on a single lethal dose, often through short-term exposure. It doesn't account for long-term, low-dose effects, cumulative toxicity, or different exposure routes. It also fails to reflect species differences, individual variability, or environmental impacts, such as changes in ecosystems. Therefore, while useful for evaluating immediate lethality, LD50 does not capture chronic health risks or ecological consequences, making it a poor descriptor for these types of toxicity.

References:

• DDT: npic.orst.edu/factsheet…

• Caffeine: pubmed.ncbi.nlm.nih.gov…

• Test No. 425: Acute Oral Toxicity: Up-and-Down Procedure - oecd.org/en/publication…

(the more you know - subject to editing and expansion)