diff --git a/src/core/CCChar.ml b/src/core/CCChar.ml
index a1622930..460d2eed 100644
--- a/src/core/CCChar.ml
+++ b/src/core/CCChar.ml
@@ -11,3 +11,13 @@ let compare = Char.compare
 
 let pp = Buffer.add_char
 let print = Format.pp_print_char
+
+let lowercase_ascii c =
+  if c >= 'A' && c <= 'Z'
+  then Char.unsafe_chr (Char. code c + 32)
+  else c
+
+let uppercase_ascii c =
+  if c >= 'a' && c <= 'z'
+  then Char.unsafe_chr (Char.code c - 32)
+  else c
diff --git a/src/core/CCChar.mli b/src/core/CCChar.mli
index 1ca8dcd3..345049b2 100644
--- a/src/core/CCChar.mli
+++ b/src/core/CCChar.mli
@@ -9,5 +9,13 @@ type t = char
 val equal : t -> t -> bool
 val compare : t -> t -> int
 
+val lowercase_ascii : t -> t
+(** See {!Char}
+    @since NEXT_RELEASE *)
+
+val uppercase_ascii : t -> t
+(** See {!Char}
+    @since NEXT_RELEASE *)
+
 val pp : Buffer.t -> t -> unit
 val print : Format.formatter -> t -> unit
diff --git a/src/core/CCString.cppo.ml b/src/core/CCString.cppo.ml
index d29da1e6..61fa8240 100644
--- a/src/core/CCString.cppo.ml
+++ b/src/core/CCString.cppo.ml
@@ -651,10 +651,20 @@ let lowercase_ascii = String.lowercase_ascii
 
 #else
 
-let capitalize_ascii = String.capitalize
-let uncapitalize_ascii = String.uncapitalize
-let uppercase_ascii = String.uppercase
-let lowercase_ascii = String.lowercase
+let capitalize_ascii s =
+  mapi
+    (fun i c -> if i=0 then CCChar.uppercase_ascii c else c)
+    s
+    
+
+let uncapitalize_ascii s =
+  mapi
+    (fun i c -> if i=0 then CCChar.lowercase_ascii c else c)
+    s
+
+let uppercase_ascii = map CCChar.uppercase_ascii
+
+let lowercase_ascii = map CCChar.lowercase_ascii
 
 #endif