diff --git a/documentation/Amplitude.html b/documentation/Amplitude.html
index 43e6667b..7378fb58 100644
--- a/documentation/Amplitude.html
+++ b/documentation/Amplitude.html
@@ -1850,7 +1850,7 @@ <h4 class="name" id="setDomain"><span class="type-signature"></span>setDomain<sp
 
 
 <div class="description">
-    Sets a customer domain for the amplitude cookie. Useful if you want to support cross-subdomain tracking.
+    Sets a customer domain for the amplitude cookie. Specified domain will include all subdomains. If you want to disable tracking for subdomains specify an empty string `''`, this will set cookies for the current domain only.
 </div>
 
 
@@ -1972,7 +1972,7 @@ <h5>Parameters:</h5>
 
     <h5>Example</h5>
     
-    <pre class="prettyprint"><code>amplitude.setDomain('.amplitude.com');</code></pre>
+    <pre class="prettyprint"><code>amplitude.setDomain('amplitude.com');</code></pre>
 
 
 
diff --git a/documentation/AmplitudeClient.html b/documentation/AmplitudeClient.html
index 743fa323..d9cf7863 100644
--- a/documentation/AmplitudeClient.html
+++ b/documentation/AmplitudeClient.html
@@ -2036,7 +2036,7 @@ <h4 class="name" id="setDomain"><span class="type-signature"></span>setDomain<sp
 
 
 <div class="description">
-    Sets a customer domain for the amplitude cookie. Useful if you want to support cross-subdomain tracking.
+    Sets a customer domain for the amplitude cookie. Specified domain will include all subdomains. If you want to disable tracking for subdomains specify an empty string `''`, this will set cookies for the current domain only.
 </div>
 
 
@@ -2156,7 +2156,7 @@ <h5>Parameters:</h5>
 
     <h5>Example</h5>
     
-    <pre class="prettyprint"><code>amplitudeClient.setDomain('.amplitude.com');</code></pre>
+    <pre class="prettyprint"><code>amplitudeClient.setDomain('amplitude.com');</code></pre>
 
 
 
diff --git a/documentation/amplitude-client.js.html b/documentation/amplitude-client.js.html
index d331b9d2..59459517 100644
--- a/documentation/amplitude-client.js.html
+++ b/documentation/amplitude-client.js.html
@@ -589,10 +589,10 @@ <h1 class="page-title">Source: amplitude-client.js</h1>
 };
 
 /**
- * Sets a customer domain for the amplitude cookie. Useful if you want to support cross-subdomain tracking.
+ * Sets a customer domain for the amplitude cookie. Specified domain will include all subdomains. If you want to disable tracking for subdomains specify an empty string `''`, this will set cookies for the current domain only.
  * @public
  * @param {string} domain to set.
- * @example amplitudeClient.setDomain('.amplitude.com');
+ * @example amplitudeClient.setDomain('amplitude.com');
  */
 AmplitudeClient.prototype.setDomain = function setDomain(domain) {
   if (!utils.validateInput(domain, 'domain', 'string')) {
diff --git a/documentation/amplitude.js.html b/documentation/amplitude.js.html
index 6b013e62..2cbd79a2 100644
--- a/documentation/amplitude.js.html
+++ b/documentation/amplitude.js.html
@@ -161,11 +161,11 @@ <h1 class="page-title">Source: amplitude.js</h1>
 };
 
 /**
- * Sets a customer domain for the amplitude cookie. Useful if you want to support cross-subdomain tracking.
+ * Sets a customer domain for the amplitude cookie. Specified domain will include all subdomains. If you want to disable tracking for subdomains specify an empty string `''`, this will set cookies for the current domain only.
  * @public
  * @param {string} domain to set.
  * @deprecated Please use amplitude.getInstance().setDomain(domain);
- * @example amplitude.setDomain('.amplitude.com');
+ * @example amplitude.setDomain('amplitude.com');
  */
 Amplitude.prototype.setDomain = function setDomain(domain) {
   this.getInstance().setDomain(domain);
diff --git a/src/amplitude-client.js b/src/amplitude-client.js
index 607975e8..6d85d350 100644
--- a/src/amplitude-client.js
+++ b/src/amplitude-client.js
@@ -718,10 +718,10 @@ AmplitudeClient.prototype.saveEvents = function saveEvents() {
 };
 
 /**
- * Sets a customer domain for the amplitude cookie. Useful if you want to support cross-subdomain tracking.
+ * Sets a customer domain for the amplitude cookie. Specified domain will include all subdomains. If you want to disable tracking for subdomains specify an empty string `''`, this will set cookies for the current domain only.
  * @public
  * @param {string} domain to set.
- * @example amplitudeClient.setDomain('.amplitude.com');
+ * @example amplitudeClient.setDomain('amplitude.com');
  */
 AmplitudeClient.prototype.setDomain = function setDomain(domain) {
   if (!utils.validateInput(domain, 'domain', 'string')) {
diff --git a/src/cookie.js b/src/cookie.js
index bae0c6ae..80da0c71 100644
--- a/src/cookie.js
+++ b/src/cookie.js
@@ -48,7 +48,7 @@ const topDomain = (url) => {
   for (let i = 0; i < levels.length; ++i) {
     const cname = '__tld_test__';
     const domain = levels[i];
-    const opts = { domain: '.' + domain };
+    const opts = { domain: domain };
 
     baseCookie.set(cname, 1, opts);
     if (baseCookie.get(cname)) {
@@ -71,7 +71,7 @@ var options = function(opts) {
   _options.expirationDays = opts.expirationDays;
   _options.secure = opts.secure;
 
-  var domain = (!utils.isEmptyString(opts.domain)) ? opts.domain : '.' + topDomain(getLocation().href);
+  var domain = (opts.domain !== undefined) ? opts.domain : topDomain(getLocation().href);
   var token = Math.random();
   _options.domain = domain;
   set('amplitude_test', token);
diff --git a/src/options.js b/src/options.js
index ebd8262a..0b3ce93e 100644
--- a/src/options.js
+++ b/src/options.js
@@ -17,7 +17,7 @@ export default {
   cookieExpiration: 365 * 10,
   cookieName: 'amplitude_id',
   deviceIdFromUrlParam: false,
-  domain: '',
+  domain: undefined,
   eventUploadPeriodMillis: 30 * 1000, // 30s
   eventUploadThreshold: 30,
   forceHttps: true,