diff --git a/src/asserts/big-number-assert.js b/src/asserts/big-number-assert.js
index 2b88777..c7b3cb7 100644
--- a/src/asserts/big-number-assert.js
+++ b/src/asserts/big-number-assert.js
@@ -26,8 +26,6 @@ module.exports = function bigNumberAssert({ validateSignificantDigits = true } =
     throw new Error('BigNumber is not installed');
   }
 
-  BigNumber.DEBUG = !!validateSignificantDigits;
-
   /**
    * Class name.
    */
@@ -39,7 +37,11 @@ module.exports = function bigNumberAssert({ validateSignificantDigits = true } =
    */
 
   this.validate = value => {
+    const bigNumberDebug = BigNumber.DEBUG;
+
     try {
+      BigNumber.DEBUG = !!validateSignificantDigits;
+
       const number = new BigNumber(value);
 
       if (Number.isNaN(number.toNumber())) {
@@ -51,6 +53,8 @@ module.exports = function bigNumberAssert({ validateSignificantDigits = true } =
       }
 
       throw new Violation(this, value);
+    } finally {
+      BigNumber.DEBUG = bigNumberDebug;
     }
 
     return true;
diff --git a/src/asserts/big-number-equal-to-assert.js b/src/asserts/big-number-equal-to-assert.js
index e9fd4b1..533ecdc 100644
--- a/src/asserts/big-number-equal-to-assert.js
+++ b/src/asserts/big-number-equal-to-assert.js
@@ -28,8 +28,6 @@ module.exports = function bigNumberEqualToAssert(value, { validateSignificantDig
     throw new Error('BigNumber is not installed');
   }
 
-  BigNumber.DEBUG = !!validateSignificantDigits;
-
   /**
    * Extend `Assert` with `BigNumberAssert`.
    */
@@ -55,7 +53,11 @@ module.exports = function bigNumberEqualToAssert(value, { validateSignificantDig
    */
 
   this.validate = value => {
+    const bigNumberDebug = BigNumber.DEBUG;
+
     try {
+      BigNumber.DEBUG = !!validateSignificantDigits;
+
       Assert.bigNumber({ validateSignificantDigits }).validate(value);
 
       const number = new BigNumber(value);
@@ -72,6 +74,8 @@ module.exports = function bigNumberEqualToAssert(value, { validateSignificantDig
       }
 
       throw new Violation(this, value, context);
+    } finally {
+      BigNumber.DEBUG = bigNumberDebug;
     }
 
     return true;
diff --git a/src/asserts/big-number-greater-than-assert.js b/src/asserts/big-number-greater-than-assert.js
index 6913629..1cf3f7f 100644
--- a/src/asserts/big-number-greater-than-assert.js
+++ b/src/asserts/big-number-greater-than-assert.js
@@ -28,8 +28,6 @@ module.exports = function bigNumberGreaterThanAssert(threshold, { validateSignif
     throw new Error('BigNumber is not installed');
   }
 
-  BigNumber.DEBUG = !!validateSignificantDigits;
-
   /**
    * Extend `Assert` with `BigNumberAssert`.
    */
@@ -55,7 +53,11 @@ module.exports = function bigNumberGreaterThanAssert(threshold, { validateSignif
    */
 
   this.validate = value => {
+    const bigNumberDebug = BigNumber.DEBUG;
+
     try {
+      BigNumber.DEBUG = !!validateSignificantDigits;
+
       Assert.bigNumber({ validateSignificantDigits }).validate(value);
 
       const number = new BigNumber(value);
@@ -72,6 +74,8 @@ module.exports = function bigNumberGreaterThanAssert(threshold, { validateSignif
       }
 
       throw new Violation(this, value, context);
+    } finally {
+      BigNumber.DEBUG = bigNumberDebug;
     }
 
     return true;
diff --git a/src/asserts/big-number-greater-than-or-equal-to-assert.js b/src/asserts/big-number-greater-than-or-equal-to-assert.js
index c44d390..e0ff094 100644
--- a/src/asserts/big-number-greater-than-or-equal-to-assert.js
+++ b/src/asserts/big-number-greater-than-or-equal-to-assert.js
@@ -28,8 +28,6 @@ module.exports = function bigNumberGreaterThanOrEqualToAssert(threshold, { valid
     throw new Error('BigNumber is not installed');
   }
 
-  BigNumber.DEBUG = !!validateSignificantDigits;
-
   /**
    * Extend `Assert` with `BigNumberAssert`.
    */
@@ -54,7 +52,11 @@ module.exports = function bigNumberGreaterThanOrEqualToAssert(threshold, { valid
    */
 
   this.validate = value => {
+    const bigNumberDebug = BigNumber.DEBUG;
+
     try {
+      BigNumber.DEBUG = !!validateSignificantDigits;
+
       Assert.bigNumber({ validateSignificantDigits }).validate(value);
 
       const number = new BigNumber(value);
@@ -71,6 +73,8 @@ module.exports = function bigNumberGreaterThanOrEqualToAssert(threshold, { valid
       }
 
       throw new Violation(this, value, context);
+    } finally {
+      BigNumber.DEBUG = bigNumberDebug;
     }
 
     return true;
diff --git a/src/asserts/big-number-less-than-assert.js b/src/asserts/big-number-less-than-assert.js
index bbef1d5..46adec0 100644
--- a/src/asserts/big-number-less-than-assert.js
+++ b/src/asserts/big-number-less-than-assert.js
@@ -28,8 +28,6 @@ module.exports = function bigNumberLessThan(threshold, { validateSignificantDigi
     throw new Error('BigNumber is not installed');
   }
 
-  BigNumber.DEBUG = !!validateSignificantDigits;
-
   /**
    * Extend `Assert` with `BigNumberAssert`.
    */
@@ -55,7 +53,11 @@ module.exports = function bigNumberLessThan(threshold, { validateSignificantDigi
    */
 
   this.validate = value => {
+    const bigNumberDebug = BigNumber.DEBUG;
+
     try {
+      BigNumber.DEBUG = !!validateSignificantDigits;
+
       Assert.bigNumber({ validateSignificantDigits }).validate(value);
 
       const number = new BigNumber(value);
@@ -72,6 +74,8 @@ module.exports = function bigNumberLessThan(threshold, { validateSignificantDigi
       }
 
       throw new Violation(this, value, context);
+    } finally {
+      BigNumber.DEBUG = bigNumberDebug;
     }
 
     return true;
diff --git a/src/asserts/big-number-less-than-or-equal-to-assert.js b/src/asserts/big-number-less-than-or-equal-to-assert.js
index 1dd7276..e5f08e2 100644
--- a/src/asserts/big-number-less-than-or-equal-to-assert.js
+++ b/src/asserts/big-number-less-than-or-equal-to-assert.js
@@ -28,8 +28,6 @@ module.exports = function bigNumberLessThanOrEqualToAssert(threshold, { validate
     throw new Error('BigNumber is not installed');
   }
 
-  BigNumber.DEBUG = !!validateSignificantDigits;
-
   /**
    * Extend `Assert` with `BigNumberAssert`.
    */
@@ -55,7 +53,11 @@ module.exports = function bigNumberLessThanOrEqualToAssert(threshold, { validate
    */
 
   this.validate = value => {
+    const bigNumberDebug = BigNumber.DEBUG;
+
     try {
+      BigNumber.DEBUG = !!validateSignificantDigits;
+
       Assert.bigNumber({ validateSignificantDigits }).validate(value);
 
       const number = new BigNumber(value);
@@ -72,6 +74,8 @@ module.exports = function bigNumberLessThanOrEqualToAssert(threshold, { validate
       }
 
       throw new Violation(this, value, context);
+    } finally {
+      BigNumber.DEBUG = bigNumberDebug;
     }
 
     return true;