TOKYO (AP) _ At least 14 people have died from taking a combination of an anti-cancer drug and a new medication to fight the disease shingles, officials said Thursday, in an indication of problems plaguing Japan's health care system.

The 14 deaths occurred within a one-month period in September and October, and were the largest number ever reported in Japan for a 30-day period from prescription drug side effects, said Kazuo Hirayama of the Health and Welfare Ministry.

Doctors and hospitals frequently over-prescribe drugs, which they sell to patients at a large profit, and critics accuse the government of being too lax in regulating drug companies, especially in introducing new drugs.

The Health and Welfare Ministry in July approved sale of the drug BV-araU, which is used for treatment of shingles, a painful disease which affects nerves and is caused by the chicken pox virus.

The drug, from the start of its distribution in Japan, carried warnings against its use with the cancer-fighting drug fluorouracil.

When three deaths were reported six weeks ago, the Japanese distributor suspended shipments of BV-araU and began a recall.

But some doctors apparently kept prescribing the two medications together, or patients took them unwittingly after receiving the drugs from different doctors.

Many Japanese doctors do not inform patients of a cancer diagnosis, and proceed with treatment without telling patients the specifics.

Because doctors and hospital receive low reimbursements from the national health insurance plan when they treat patients, they tend to over-prescribe drugs, which they often acquire at discount, to make money.

Patients often receive four or five kinds of medicines at once, frequently the most expensive and potent versions, with little regard for side effects and little cross-checking with previous prescriptions.

Following a score of scandals involving drug side effects, critics also charge the government with insufficiently regulating drug companies.

The patients who died were outpatients aged 51 to 81.

Nippon Shoji Kaisha, the co-developer and sole distributor of the BV-araU drug in Japan, said it suspended shipment on Oct. 12 and began recalling 500,000 tablets from about 10,000 hospitals and institutes nationwide.

Susumu Shibuya, spokesman of Yamasa Corp., a major Japanese soy sauce maker and a co-developer, said New York-based Bristol-Myers Squibb Co. is conducting worldwide clinical tests of the drug under the product names Usevir and Sorivudine.

The U.S. company has licensed worldwide BV-araU development and marketing rights outside Japan, Shibuya said.