Castleman disease (CD) is a rare lymphoproliferative disorder with multiple subtypes. Thrombocytopenia, anasarca, fever, reticulin fibrosis or renal insufficiency, and organomegaly (TAFRO) syndrome can occur in the context of CD. The study evaluated worldwide public awareness of CD and TAFRO syndrome using Google Trends data between 2015 and 2021. Our results showed that global public interest steadily grew until late 2019, at a small but significant rate of 1.1% per month from the 1st to 57th month (1/2015-9/2019). The increase coincided with a peak in the United States and Japan, but the search volume decreased at a rate of 1.3% per month after that time. No clear trend changes were noted throughout the study period with the search term "TAFRO." However, the search volume significantly increased during the time period at a rate of 4.8% (confidence interval [CI]: 2.8, 6.8) and 4.7% (CI: 2.7, 6.8) per month in Japan and worldwide, respectively. There was an insufficient search volume for "TAFRO" in the United States to perform the analysis. Most searches on "TAFRO" stemmed from Japan, suggesting considerable geographical disparity in the awareness of TAFRO syndrome. Further efforts are crucial to raise the awareness of CD and TAFRO syndrome among physicians and the general public, primarily in non-USA and Japanese countries.