Canadian scientists have found that rats fed the artificial sweetner saccharin have developed bladder stones and tumore. Canadian authorities have asked American scientists to fly to Canada to examine the test data.

Both U.S. and Canadian scientists have said they do not yet know if there is any significance to the tumors.

Dr. Richard Bates, one of the U.S. Food and Drug Administration researchers going to Ottawa on Monday said "they've got enough concern with the results of these studies that they think they should be looked at."

However, when told of concern at FDA over the reported results of the Canadian studies Dr. Ian Munro, head of the toxicology of the FDA, would only say "they get worked up about things we don't get worked up about."

There have been previous studies, with animals by both Canadian and American scientists, which have also turned up apparent links between the ingestion of saccharin and the appearance of tumors.

The FDA, however, has repeatedly postponed taking any action on the use of distribution of the artificial sweetener, found in all diet drinks and consumed at the rate of about five million pounds a year in the United States, pending the results of further testing. The current Canadian tests are those to which FDA has deferred.

Friday, rumors that the Canadians were about to ban the use of the sweetener caused the stock prices of at least five major American soft drink manufacturers to plummet.

Coca Cola stock dropped from 80 1/4 to 76 3/4. Pepsi, Seven Up and Royal Crown Cola stock also dropped significantly.

One of the possible significant elements of the Canadian study is that the saccharin fed the rats who developed tumors was free of an impurity usually found in saccharin. In past studies, the imputity, ortho-tolenesulfonomide, rather than the saccharin, has been blamed for the tumors.

Asked about the signifcanee of this week's meetings, an FDA official said "of course they're not calling us up there for irreleyant things."