diff --git a/src/MarkdownAst.elm b/src/MarkdownAst.elm
index 5ceb5d1..80107cb 100644
--- a/src/MarkdownAst.elm
+++ b/src/MarkdownAst.elm
@@ -343,7 +343,12 @@ normalizePlainText rawStr =
 
         hasLastSpace =
             String.right 1 rawStr
-                |> String.any isWhiteSpace
+                -- `|> String.any isWhiteSpace` may cause infinite loop
+                |> String.foldl
+                    (\c acc ->
+                        acc || isWhiteSpace c
+                    )
+                    False
 
         words =
             case normalizedWords rawStr of
diff --git a/src/Sample.elm b/src/Sample.elm
index 7b18432..d04518f 100644
--- a/src/Sample.elm
+++ b/src/Sample.elm
@@ -28,7 +28,7 @@ myMarkdown =
                         { ordered = False
                         , items =
                             [ { content =
-                                    [ Ast.PlainText "List Item 1"
+                                    [ Ast.PlainText "List Item 1😈"
                                     ]
                               , children =
                                     [ Ast.ListBlock
diff --git a/tests/MarkdownAstSuite.elm b/tests/MarkdownAstSuite.elm
index ea75ba8..0e511fb 100644
--- a/tests/MarkdownAstSuite.elm
+++ b/tests/MarkdownAstSuite.elm
@@ -18,7 +18,7 @@ Markdown AST represents *Markdown* AST.
 
 ## Section
 
-* List Item 1
+* List Item 1😈
     1. Child item
 * List Item 2