Ten deaths sounds low. Does that mean it is safe?

It means ten were reported as suspected to be treatment-related. It does not establish a rate, because the denominator — how many people received treatment — is not published, and events occurring after patients return home are unlikely to be captured at all.

What should I ask before treatment, in one question?

“Which hospital do you transfer me to in an emergency, and what is your follow-up procedure once I have returned to my country?” Get it in writing. Only a small minority of clinics publish this unprompted.

Risks, reported numbers, and the question before you fly home

Japan requires clinics to report serious events to the national government, which means there are real numbers here rather than reassurance. They are small numbers. They are also incomplete in a specific way that matters if you are travelling.

The reporting duty and the numbers

A clinic must report a death or a serious event suspected to be caused by the treatment to the national government within seven days. Cumulatively through March 2025, 10 deaths were reported in treatment and 6 in research, out of 95 reports in total.

These are reports of suspected causation, not confirmed causes of death. They are also, necessarily, reports of events that occurred while the patient was still in the system. Which brings us to the part that concerns visitors specifically.

The gap that affects travellers

If a delayed reaction occurs after you have flown home, the Japanese clinic may never learn of it and it will not appear in these figures. That is not a criticism of the reporting system — it is a structural limit of it, and it means the numbers understate what happens to people who leave.

Ask the clinic directly what follow-up it offers after you return, in what language, and who reads the message.

Only 13 of 550 publish their emergency arrangement

Most of these treatments are given in small clinics without inpatient beds. If something acute happens, the clinic transfers you. In our review of 550 clinic websites, only 13 published which hospital that would be.

This is the single most useful question you can ask, and it takes one sentence. If the answer is vague, that tells you something about how the risk has been planned for.

Administrative actions are published

The Ministry of Health, Labour and Welfare publishes administrative actions taken against providers. There are 11 on record, 5 of them against medical institutions, in categories including improvement orders and suspension. We list them, and we flag any institution on our register that has one.

See published administrative actions

Common questions

Ten deaths sounds low. Does that mean it is safe?: It means ten were reported as suspected to be treatment-related. It does not establish a rate, because the denominator — how many people received treatment — is not published, and events occurring after patients return home are unlikely to be captured at all.
What should I ask before treatment, in one question?: “Which hospital do you transfer me to in an emergency, and what is your follow-up procedure once I have returned to my country?” Get it in writing. Only a small minority of clinics publish this unprompted.

Sources: Act on the Safety of Regenerative Medicine (reporting duty); reports to the Health Sciences Council of the Ministry of Health, Labour and Welfare; MHLW published administrative actions; our own review of 550 clinic websites.

This page is a summary for visitors from outside Japan. The Japanese pages are the authoritative version and are kept more current. All figures come from the Ministry of Health, Labour and Welfare register and from our own review of clinic websites.