diff --git a/zio-http/shared/src/main/scala/zio/http/Body.scala b/zio-http/shared/src/main/scala/zio/http/Body.scala
index a72fdce456..9f000e7032 100644
--- a/zio-http/shared/src/main/scala/zio/http/Body.scala
+++ b/zio-http/shared/src/main/scala/zio/http/Body.scala
@@ -315,10 +315,11 @@ object Body {
     form: Form,
   )(implicit trace: Trace): UIO[Body] =
     form.multipartBytesUUID.map { case (boundary, bytes) =>
+      val validBoundary = boundary.replaceAll("[^a-zA-Z0-9'()+_,-./:=?]", "-")
       StreamBody(
         bytes,
         knownContentLength = None,
-        Some(Body.ContentType(MediaType.multipart.`form-data`, Some(boundary))),
+        Some(Body.ContentType(MediaType.multipart.`form-data`, Some(validBoundary))),
       )
     }
 
@@ -466,7 +467,7 @@ object Body {
 
     override def isEmpty: Boolean = true
 
-    override def toString: String = "Body.empty"
+    override def toString(): String = "Body.empty"
 
     override private[zio] def unsafeAsArray(implicit unsafe: Unsafe): Array[Byte] = Array.empty[Byte]
 
@@ -513,7 +514,7 @@ object Body {
     override def asStream(implicit trace: Trace): ZStream[Any, Throwable, Byte] =
       ZStream.unwrap(asChunk.map(ZStream.fromChunk(_)))
 
-    override def toString: String = s"Body.fromChunk($data)"
+    override def toString(): String = s"Body.fromChunk($data)"
 
     override private[zio] def unsafeAsArray(implicit unsafe: Unsafe): Array[Byte] = data.toArray
 
@@ -538,7 +539,7 @@ object Body {
     override def asStream(implicit trace: Trace): ZStream[Any, Throwable, Byte] =
       ZStream.unwrap(asChunk.map(ZStream.fromChunk(_)))
 
-    override def toString: String = s"Body.fromArray($data)"
+    override def toString(): String = s"Body.fromArray($data)"
 
     override private[zio] def unsafeAsArray(implicit unsafe: Unsafe): Array[Byte] = data