diff --git a/components/lib/badge/Badge.d.ts b/components/lib/badge/Badge.d.ts
index 4277194d34..f3476d6d56 100644
--- a/components/lib/badge/Badge.d.ts
+++ b/components/lib/badge/Badge.d.ts
@@ -1,6 +1,6 @@
 import * as React from 'react';
 
-type BadgeSeverityType = 'success' | 'info' | 'warn' | 'error' | (string & {});
+type BadgeSeverityType = 'success' | 'info' | 'warn' | 'error';
 
 type BadgeSizeType = 'normal' | 'large' | 'xlarge';
 
diff --git a/components/lib/message/Message.d.ts b/components/lib/message/Message.d.ts
index 21851ebe8c..b6591f8ae0 100644
--- a/components/lib/message/Message.d.ts
+++ b/components/lib/message/Message.d.ts
@@ -1,6 +1,6 @@
 import * as React from 'react';
 
-type MessageSeverityType = 'success' | 'info' | 'warn' | 'error' | (string & {});
+type MessageSeverityType = 'success' | 'info' | 'warn' | 'error';
 
 type MessageContentType = React.ReactNode | ((props: MessageProps) => React.ReactNode);
 
diff --git a/components/lib/messages/Messages.d.ts b/components/lib/messages/Messages.d.ts
index 212caa844a..47700070d1 100644
--- a/components/lib/messages/Messages.d.ts
+++ b/components/lib/messages/Messages.d.ts
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { CSSTransitionProps } from '../csstransition';
 
-type MessagesSeverityType = 'success' | 'info' | 'warn' | 'error' | (string & {});
+type MessagesSeverityType = 'success' | 'info' | 'warn' | 'error';
 
 type MessagesMessageType = MessagesMessage | MessagesMessage[];
 
diff --git a/components/lib/tag/Tag.d.ts b/components/lib/tag/Tag.d.ts
index 349b9e42cf..0d2494d2ef 100644
--- a/components/lib/tag/Tag.d.ts
+++ b/components/lib/tag/Tag.d.ts
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { IconType } from '../utils';
 
-type TagSeverityType = 'success' | 'info' | 'warn' | 'error' | (string & {});
+type TagSeverityType = 'success' | 'info' | 'warn' | 'error';
 
 export interface TagProps {
     value?: React.ReactNode;
diff --git a/components/lib/toast/Toast.d.ts b/components/lib/toast/Toast.d.ts
index 0e241354eb..0b106e3791 100644
--- a/components/lib/toast/Toast.d.ts
+++ b/components/lib/toast/Toast.d.ts
@@ -1,7 +1,7 @@
 import * as React from 'react';
 import { CSSTransitionProps } from '../csstransition';
 
-type ToastSeverityType = 'success' | 'info' | 'warn' | 'error' | (string & {});
+type ToastSeverityType = 'success' | 'info' | 'warn' | 'error';
 
 type ToastMessageType = ToastMessage | ToastMessage[];