A brief comment is made on the National Guidelines for Numerical National Water Quality Criteria. The Guidelines state that the phytotoxicity test procedure has not been well developed, yet indicate that plant species are not as sensitive to toxicity as animals. The author contends that it is too early to draw a conclusion on the sensitivity of plant toxicity tests. The objective approach for the National Guidelines to take is to encourage further studies so that a better assessment can be made when more results are available.