diff --git a/src/Microsoft.AspNetCore.Http/Internal/DefaultHttpResponse.cs b/src/Microsoft.AspNetCore.Http/Internal/DefaultHttpResponse.cs
index 9b664111..e4cdf241 100644
--- a/src/Microsoft.AspNetCore.Http/Internal/DefaultHttpResponse.cs
+++ b/src/Microsoft.AspNetCore.Http/Internal/DefaultHttpResponse.cs
@@ -81,7 +81,7 @@ public override string ContentType
             }
             set
             {
-                if (string.IsNullOrWhiteSpace(value))
+                if (string.IsNullOrEmpty(value))
                 {
                     HttpResponseFeature.Headers.Remove(HeaderNames.ContentType);
                 }