diff --git a/packages/core/src/consumed-thing.ts b/packages/core/src/consumed-thing.ts
index 5fafe9653..8c03f3938 100644
--- a/packages/core/src/consumed-thing.ts
+++ b/packages/core/src/consumed-thing.ts
@@ -558,7 +558,7 @@ export default class ConsumedThing extends TD.Thing implements IConsumedThing {
 
         const content = await client.readResource(form);
         try {
-            return this.handleInteractionOutput(content, form, tp);
+            return this.handleInteractionOutput(content, form, tp, false);
         } catch (e) {
             const error = e instanceof Error ? e : new Error(JSON.stringify(e));
             throw new Error(`Error while processing property for ${tp.title}. ${error.message}`);
@@ -568,7 +568,8 @@ export default class ConsumedThing extends TD.Thing implements IConsumedThing {
     private handleInteractionOutput(
         content: Content,
         form: TD.Form,
-        outputDataSchema: WoT.DataSchema | undefined
+        outputDataSchema: WoT.DataSchema | undefined,
+        ignoreValidation: boolean
     ): InteractionOutput {
         // infer media type from form if not in response metadata
         content.type ??= form.contentType ?? "application/json";
@@ -583,7 +584,7 @@ export default class ConsumedThing extends TD.Thing implements IConsumedThing {
                 );
             }
         }
-        return new InteractionOutput(content, form, outputDataSchema);
+        return new InteractionOutput(content, form, outputDataSchema, { ignoreValidation });
     }
 
     async _readProperties(propertyNames: string[]): Promise<WoT.PropertyReadMap> {
@@ -703,7 +704,8 @@ export default class ConsumedThing extends TD.Thing implements IConsumedThing {
 
         const content = await client.invokeResource(form, input);
         try {
-            return this.handleInteractionOutput(content, form, ta.output);
+            const ignoreValidation = ta.synchronous === undefined ? true : !ta.synchronous;
+            return this.handleInteractionOutput(content, form, ta.output, ignoreValidation);
         } catch (e) {
             const error = e instanceof Error ? e : new Error(JSON.stringify(e));
             throw new Error(`Error while processing action for ${ta.title}. ${error.message}`);
@@ -746,7 +748,7 @@ export default class ConsumedThing extends TD.Thing implements IConsumedThing {
             // next
             (content) => {
                 try {
-                    listener(this.handleInteractionOutput(content, form, tp));
+                    listener(this.handleInteractionOutput(content, form, tp, false));
                 } catch (e) {
                     const error = e instanceof Error ? e : new Error(JSON.stringify(e));
                     warn(`Error while processing observe property for ${tp.title}. ${error.message}`);
@@ -802,7 +804,7 @@ export default class ConsumedThing extends TD.Thing implements IConsumedThing {
             formWithoutURITemplates,
             (content) => {
                 try {
-                    listener(this.handleInteractionOutput(content, form, te.data));
+                    listener(this.handleInteractionOutput(content, form, te.data, false));
                 } catch (e) {
                     const error = e instanceof Error ? e : new Error(JSON.stringify(e));
                     warn(`Error while processing event for ${te.title}. ${error.message}`);
diff --git a/packages/core/src/interaction-output.ts b/packages/core/src/interaction-output.ts
index 3a2d1768f..9f36c258a 100644
--- a/packages/core/src/interaction-output.ts
+++ b/packages/core/src/interaction-output.ts
@@ -42,6 +42,7 @@ export class InteractionOutput implements WoT.InteractionOutput {
     dataUsed: boolean;
     form?: WoT.Form;
     schema?: WoT.DataSchema;
+    ignoreValidation: boolean; // by default set to false
 
     public get data(): ReadableStream {
         if (this.#stream) {
@@ -57,10 +58,11 @@ export class InteractionOutput implements WoT.InteractionOutput {
         return (this.#stream = ProtocolHelpers.toWoTStream(this.#content.body) as ReadableStream);
     }
 
-    constructor(content: Content, form?: WoT.Form, schema?: WoT.DataSchema) {
+    constructor(content: Content, form?: WoT.Form, schema?: WoT.DataSchema, options = { ignoreValidation: false }) {
         this.#content = content;
         this.form = form;
         this.schema = schema;
+        this.ignoreValidation = options.ignoreValidation ?? false;
         this.dataUsed = false;
     }
 
@@ -122,7 +124,7 @@ export class InteractionOutput implements WoT.InteractionOutput {
         // validate the schema
         const validate = ajv.compile<T>(this.schema);
 
-        if (!validate(json)) {
+        if (!this.ignoreValidation && !validate(json)) {
             debug(`schema = ${util.inspect(this.schema, { depth: 10, colors: true })}`);
             debug(`value: ${json}`);
             debug(`Errror: ${validate.errors}`);
@@ -130,6 +132,6 @@ export class InteractionOutput implements WoT.InteractionOutput {
         }
 
         this.#value = json;
-        return json;
+        return json as T;
     }
 }
diff --git a/packages/core/test/ClientTest.ts b/packages/core/test/ClientTest.ts
index f13e5f829..ec7bfecac 100644
--- a/packages/core/test/ClientTest.ts
+++ b/packages/core/test/ClientTest.ts
@@ -108,6 +108,18 @@ const myThingDesc = {
                 },
             ],
         },
+        anAsyncAction: {
+            input: { type: "integer" },
+            output: { type: "integer" },
+            synchronous: false,
+            forms: [
+                {
+                    href: "testdata://host/athing/actions/anasyncaction",
+                    mediaType: "application/json",
+                    response: { contentType: "application/json" },
+                },
+            ],
+        },
     },
     events: {
         anEvent: {
@@ -510,6 +522,28 @@ class WoTClientTest {
         }
     }
 
+    @test async "call an async action"() {
+        // should not throw Error: Invalid value according to DataSchema
+        WoTClientTest.clientFactory.setTrap(async (form: Form, content: Content) => {
+            const valueData = await content.toBuffer();
+            expect(valueData.toString()).to.equal("23");
+            return new Content("application/json", Readable.from(Buffer.from(JSON.stringify({ status: "pending" }))));
+        });
+        const td = (await WoTClientTest.WoTHelpers.fetch("td://foo")) as ThingDescription;
+
+        const thing = await WoTClientTest.WoT.consume(td);
+
+        expect(thing).to.have.property("title").that.equals("aThing");
+        expect(thing).to.have.property("actions").that.has.property("anAction");
+
+        // deal with ActionStatus object
+        const result = await thing.invokeAction("anAsyncAction", 23);
+        // eslint-disable-next-line no-unused-expressions
+        expect(result).not.to.be.null;
+        const value = await result?.value();
+        expect(value).to.have.property("status");
+    }
+
     @test async "subscribe to event"() {
         WoTClientTest.clientFactory.setTrap(() => {
             return new Content("application/json", Readable.from(Buffer.from("triggered")));
diff --git a/packages/core/test/InteractionOutputTest.ts b/packages/core/test/InteractionOutputTest.ts
index 0d66b39dd..931317cbe 100644
--- a/packages/core/test/InteractionOutputTest.ts
+++ b/packages/core/test/InteractionOutputTest.ts
@@ -20,6 +20,7 @@ import { expect, use } from "chai";
 import { Readable } from "stream";
 import { InteractionOutput } from "../src/interaction-output";
 import { Content } from "..";
+import { fail } from "assert";
 
 use(promised);
 const delay = (ms: number) => {
@@ -106,6 +107,30 @@ class InteractionOutputTests {
         expect(result).be.true;
     }
 
+    @test async "should fail returning unexpected value with no validation"() {
+        const stream = Readable.from(Buffer.from("not boolean", "utf-8"));
+        const content = new Content("application/json", stream);
+
+        const out = new InteractionOutput(content, {}, { type: "boolean" }); // ignoreValidation false by default
+        try {
+            const result = await out.value();
+            expect(result).be.true;
+            fail("Wrongly allows invalid value");
+        } catch {
+            // expected to throw
+        }
+    }
+
+    @test async "should accept returning unexpected value with no validation"() {
+        // type boolean should not throw since we set ignoreValidation to true
+        const stream = Readable.from(Buffer.from("not boolean", "utf-8"));
+        const content = new Content("application/json", stream);
+
+        const out = new InteractionOutput(content, {}, { type: "boolean" }, { ignoreValidation: true });
+        const result = await out.value();
+        expect(result).to.eql("not boolean");
+    }
+
     @test async "should data be used after arrayBuffer"() {
         const stream = Readable.from(Buffer.from("true", "utf-8"));
         const content = new Content("application/json", stream);