diff --git a/README.md b/README.md
index da199e9..aa20fbe 100644
--- a/README.md
+++ b/README.md
@@ -57,10 +57,10 @@ type Placeholder = {
 };
 ```
 
-show placeholder while loading.
+show placeholder while loading, either `thumbhash` or `blurhash`
 
-- [blurhash](https://blurha.sh/)
 - [thumbhash](https://evanw.github.io/thumbhash/)
+- [blurhash](https://blurha.sh/)
 
 ### `cachePolicy?: enum`
 
diff --git a/src/TurboImage.tsx b/src/TurboImage.tsx
index 69e491d..2ec79b8 100644
--- a/src/TurboImage.tsx
+++ b/src/TurboImage.tsx
@@ -44,6 +44,10 @@ const TurboImage = (props: TurboImageProps) => {
     ...restProps
   } = props;
 
+  if (placeholder && Object.keys(placeholder).length > 1) {
+    throw new Error('Choose one hash string, either thumbhash or blurhash');
+  }
+
   const processedIndicator =
     indicator && Object.keys(indicator).length !== 0
       ? {