diff --git a/syntax/vimwiki.vim b/syntax/vimwiki.vim
index 512aad9..6a2f9cf 100644
--- a/syntax/vimwiki.vim
+++ b/syntax/vimwiki.vim
@@ -383,7 +383,7 @@ hi def link VimwikiBoldT VimwikiBold
 hi def VimwikiItalic term=italic cterm=italic gui=italic
 hi def link VimwikiItalicT VimwikiItalic
 
-hi def VimwikiBoldItalic term=bold cterm=bold gui=bold,italic
+hi def VimwikiBoldItalic term=bold,italic cterm=bold,italic gui=bold,italic
 hi def link VimwikiItalicBold VimwikiBoldItalic
 hi def link VimwikiBoldItalicT VimwikiBoldItalic
 hi def link VimwikiItalicBoldT VimwikiBoldItalic
diff --git a/syntax/vimwiki_markdown.vim b/syntax/vimwiki_markdown.vim
index 0740712..05e1f34 100644
--- a/syntax/vimwiki_markdown.vim
+++ b/syntax/vimwiki_markdown.vim
@@ -31,18 +31,18 @@ let s:markdown_syntax.char_italic = '\*\|_'
 
 " text: *_bold italic_* or _*italic bold*_
 let s:markdown_syntax.rxBoldItalic = '\%(^\|\s\|[[:punct:]]\)\@<='.
-      \'\*_'.
-      \'\%([^*_`[:space:]][^*_`]*[^*_`[:space:]]\|[^*_`[:space:]]\)'.
-      \'_\*'.
+      \'\(\*\)\{3\}'.
+      \'\%([^*`[:space:]][^*`]*[^*`[:space:]]\|[^*`[:space:]]\)'.
+      \'\1\{3\}'.
       \'\%([[:punct:]]\|\s\|$\)\@='
-let s:markdown_syntax.char_bolditalic = '\*_'
+let s:markdown_syntax.char_bolditalic = '\*\*\*'
 
 let s:markdown_syntax.rxItalicBold = '\%(^\|\s\|[[:punct:]]\)\@<='.
-      \'_\*'.
-      \'\%([^*_`[:space:]][^*_`]*[^*_`[:space:]]\|[^*_`[:space:]]\)'.
-      \'\*_'.
+      \'\(_\)\{3\}'.
+      \'\%([^_`[:space:]][^_`]*[^_`[:space:]]\|[^_`[:space:]]\)'.
+      \'\1\{3\}'.
       \'\%([[:punct:]]\|\s\|$\)\@='
-let s:markdown_syntax.char_italicbold = '_\*'
+let s:markdown_syntax.char_italicbold = '___'
 
 " text: `code`
 let s:markdown_syntax.rxCode = '`[^`]\+`'