diff --git a/packages/mermaid/src/diagrams/common/common.ts b/packages/mermaid/src/diagrams/common/common.ts
index fd76d0a45d..dc37024b1a 100644
--- a/packages/mermaid/src/diagrams/common/common.ts
+++ b/packages/mermaid/src/diagrams/common/common.ts
@@ -83,7 +83,7 @@ export const sanitizeText = (text: string, config: MermaidConfig): string => {
     return text;
   }
   if (config.dompurifyConfig) {
-    text = DOMPurify.sanitize(sanitizeMore(text, config), config.dompurifyConfig).toString();
+    text = String(DOMPurify.sanitize(sanitizeMore(text, config), config.dompurifyConfig));
   } else {
     text = DOMPurify.sanitize(sanitizeMore(text, config), {
       FORBID_TAGS: ['style'],