In the March 2012 issue, the article entitled “Korea okays stem cell therapies despite limited peer-review data” (Nat. Med. 18, 329, 2012), failed to convey that the 26% improvement in knee function was an additional gain compared to the control group. The sentence should have read: “In an 89-person Korean clinical trial, 26% more people who received the Medipost treatment experienced an improvement in knee function on a widely used cartilage repair assessment scale compared with those who underwent knee surgery alone.” The piece also referred to Francis Han by her Korean name, Han Sung-ho, and did not specify that she is in charge of research and development strategy. The error has been corrected in the HTML and PDF versions of the article. Additionally, as a clarification, the cells referred to as 'banked' in the piece are frozen-stored and do not require donor-recipient matching.

In the May 2012 issue, in the piece “New biologic drugs get under the skin of psoriasis'” (Nat. Med. 18, 638, 2012), sales numbers mistakenly cited for the US psoriasis market were actually sales numbers for the G7 (US, UK, France, Germany, Italy, Spain and Japan) markets. The correct numbers for the US market are $2.6 billion in 2010 and more than $5.6 billion in 2020 (rather than $3.9 billion in 2010 and more than $7.4 billion in 2020). The error has been corrected in the HTML and PDF versions of the article.