BERLIN (AP) — Berlin’s renowned Charite hospital said Monday it plans to investigate allegations that patients in communist East Germany were used as unwitting guinea pigs in medical trials for Western drug companies.

Claims that the dictatorship allowed tests that would have been considered unethical or even illegal in the West were first made shortly after German reunification in 1990, but no wrongdoing was found at the time.

The issue surfaced again this week after German weekly Der Spiegel reported that previously unpublished documents showed at least 50,000 patients — including premature babies — were involved in more than 600 trials at dozens of hospitals. The documents came from private collections, archives of the former East German Health Ministry, the Stasi secret police and the country’s pharmaceutical authority, the magazine said. It didn’t post copies online but included excerpts in its printed edition.

A Charite spokeswoman said the hospital has now ordered the customary shredding of old patient files be stopped. Charite was by far the biggest hospital in what used to be East Germany.

“A proper scientific study is planned, but we are waiting for funding,” Manuela Zingl said.

Der Spiegel reported that East German authorities established a special office in 1983 to deal with Western companies wanting to conduct the medical trials in the country, which was steadily falling behind capitalist West Germany in scientific and economic terms.

The money from each trial — up to 800,000 West German marks, according to the magazine — was split between the East German government and the 50 hospitals involved.

Similar trials would have been far more expensive and maybe even impossible in West Germany because of widespread concerns at the time about the safety of drugs following the thalidomide scandal, which had caused thousands of babies to be born without limbs.

Der Spiegel reported that the companies involved included Germany’s Boehringer Ingelheim and Bayer AG, as well as firms later acquired by Roche Group and Novartis AG in Switzerland, and by Sanofi of France.

Eric Althoff, a spokesman for Novartis, said the company adhered to ethical principles and laws when conducting clinical trials, but that it was willing to cooperate with authorities investigating the allegations. Der Spiegel reported that antidepressants made by Ciba Geigy, now part of Novartis, were tested on mental patients during periods when they would have been unable to provide informed consent.

A spokesman for Bayer said that all of its clinical trials conformed to global standards “to the best of our knowledge.”

“With regard to any studies conducted in the past in the German Democratic Republic on behalf of our company or the former Schering AG, we assume that the standards that applied at the time — in particular the legal requirements in the former GDR — were met,” Oliver Renner said.

Boehringer Ingelheim said it was investigating the Spiegel report, but insisted that all trials would have conformed to international standards.

Roche and Sanofi didn’t immediately respond to requests for comment.

Finding detailed records on the medical trials is likely to prove difficult.

Germany’s Health Ministry said it couldn’t confirm or deny Der Spiegel’s figures for the numbers of patients involved in such trials because there had been no requirement to register them in the former West Germany.

What information remains would have to come from hospital records or those left over from the communist government in East Germany.