diff --git a/src/rules.ts b/src/rules.ts
index 686efb61bd..2181cf510b 100644
--- a/src/rules.ts
+++ b/src/rules.ts
@@ -243,7 +243,7 @@ const br = /^( {2,}|\\)\n(?!\s*$)/;
 const inlineText = /^(`+|[^`])(?:(?= {2,}\n)|[\s\S]*?(?:(?=[\\<!\[`*_]|\b_|$)|[^ ](?= {2,}\n)))/;
 
 // list of unicode punctuation marks, plus any missing characters from CommonMark spec
-const _punctuation = '\\p{P}\\p{S}';
+const _punctuation = /\p{P}\p{S}/u;
 const punctuation = edit(/^((?![*_])[\spunctuation])/, 'u')
   .replace(/punctuation/g, _punctuation).getRegex();