diff --git a/packages/nodes-base/nodes/Function/Function.node.ts b/packages/nodes-base/nodes/Function/Function.node.ts
index 649ec70ee9..0ce45f9f1a 100644
--- a/packages/nodes-base/nodes/Function/Function.node.ts
+++ b/packages/nodes-base/nodes/Function/Function.node.ts
@@ -1,5 +1,6 @@
 import { IExecuteFunctions } from 'n8n-core';
 import {
+	IDataObject,
 	INodeExecutionData,
 	INodeType,
 	INodeTypeDescription,
@@ -58,6 +59,21 @@ return items;`,
 		// Copy the items as they may get changed in the functions
 		items = JSON.parse(JSON.stringify(items));
 
+		const cleanupData = (inputData: IDataObject): IDataObject => {
+			Object.keys(inputData).map(key => {
+				if (inputData[key] !== null && typeof inputData[key] === 'object') {
+					if (inputData[key]!.constructor.name === 'Object') {
+						// Is regular node.js object so check its data
+						inputData[key] = cleanupData(inputData[key] as IDataObject);
+					} else {
+						// Is some special object like a Date so stringify
+						inputData[key] = JSON.parse(JSON.stringify(inputData[key]));
+					}
+				}
+			});
+			return inputData;
+		};
+
 		// Define the global objects for the custom function
 		const sandbox = {
 			getNodeParameter: this.getNodeParameter,
@@ -117,6 +133,9 @@ return items;`,
 				if (typeof item.json !== 'object') {
 					throw new NodeOperationError(this.getNode(), 'The json-property has to be an object!');
 				}
+
+				item.json = cleanupData(item.json);
+
 				if (item.binary !== undefined) {
 					if (Array.isArray(item.binary) || typeof item.binary !== 'object') {
 						throw new NodeOperationError(this.getNode(), 'The binary-property has to be an object!');
@@ -143,9 +162,6 @@ return items;`,
 			}
 		}
 
-
-
-
 		return this.prepareOutputData(items);
 	}
 }
diff --git a/packages/nodes-base/nodes/FunctionItem/FunctionItem.node.ts b/packages/nodes-base/nodes/FunctionItem/FunctionItem.node.ts
index 2ae9fba283..da582fdabb 100644
--- a/packages/nodes-base/nodes/FunctionItem/FunctionItem.node.ts
+++ b/packages/nodes-base/nodes/FunctionItem/FunctionItem.node.ts
@@ -58,6 +58,21 @@ return item;`,
 		const length = items.length as unknown as number;
 		let item: INodeExecutionData;
 
+		const cleanupData = (inputData: IDataObject): IDataObject => {
+			Object.keys(inputData).map(key => {
+				if (inputData[key] !== null && typeof inputData[key] === 'object') {
+					if (inputData[key]!.constructor.name === 'Object') {
+						// Is regular node.js object so check its data
+						inputData[key] = cleanupData(inputData[key] as IDataObject);
+					} else {
+						// Is some special object like a Date so stringify
+						inputData[key] = JSON.parse(JSON.stringify(inputData[key]));
+					}
+				}
+			});
+			return inputData;
+		};
+
 		for (let itemIndex = 0; itemIndex < length; itemIndex++) {
 			try {
 				item = items[itemIndex];
@@ -145,7 +160,7 @@ return item;`,
 				}
 
 				const returnItem: INodeExecutionData = {
-					json: jsonData,
+					json: cleanupData(jsonData),
 				};
 
 				if (item.binary) {