diff --git a/ippisite/db.sqlite3.REMOVED.git-id b/ippisite/db.sqlite3.REMOVED.git-id
index c1bdd06702574393a7da9e73d796265191e83b96..b036b8e867da8c9ad877493325a5ff6d0c9377fa 100644
--- a/ippisite/db.sqlite3.REMOVED.git-id
+++ b/ippisite/db.sqlite3.REMOVED.git-id
@@ -1 +1 @@
-3c03e4dd1b0b5391fa56e19cb7c4c3740ce690cd
\ No newline at end of file
+d24a740b4ee4b892f35e7e1471fec79142340ad3
\ No newline at end of file
diff --git a/ippisite/ippidb/migrations/0004_auto_20180727_0656.py b/ippisite/ippidb/migrations/0004_auto_20180727_0656.py
new file mode 100644
index 0000000000000000000000000000000000000000..98ce6d06722d8254968ef1f3322c7fb673fd39f6
--- /dev/null
+++ b/ippisite/ippidb/migrations/0004_auto_20180727_0656.py
@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11 on 2018-07-27 06:56
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('ippidb', '0003_auto_20180726_1755'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='compound',
+            name='canonical_smile',
+            field=models.TextField(unique=True, verbose_name='Canonical Smile'),
+        ),
+        migrations.AlterField(
+            model_name='mddrcompoundimport',
+            name='canonical_smile',
+            field=models.TextField(blank=True, null=True, verbose_name='Canonical Smile'),
+        ),
+        migrations.AlterField(
+            model_name='mddrsimilarity',
+            name='canonical_smile_ippidb',
+            field=models.TextField(blank=True, null=True, unique=True, verbose_name='Canonical Smile for IPPIDB compound'),
+        ),
+        migrations.AlterField(
+            model_name='mddrsimilarity',
+            name='canonical_smile_mddr',
+            field=models.TextField(blank=True, null=True, unique=True, verbose_name='Canonical Smile for MDDR Compound'),
+        ),
+    ]
diff --git a/ippisite/ippidb/models.py b/ippisite/ippidb/models.py
index 8d4c4aaadd9a10cf101330d2dd641da3b424b2c0..0547a5620cfeac98a30e1a576fcb96c0801fd0b6 100644
--- a/ippisite/ippidb/models.py
+++ b/ippisite/ippidb/models.py
@@ -264,8 +264,8 @@ class PpiComplex(models.Model):
 
 
 class Compound(models.Model):
-    canonical_smile = models.CharField(
-        'Canonical Smile', unique=True, max_length=500)
+    canonical_smile = models.TextField(
+        'Canonical Smile', unique=True)
     is_macrocycle = models.BooleanField('Contains one or more macrocycles')
     aromatic_ratio = models.DecimalField(
         'Aromatic ratio', max_digits=3, decimal_places=2)
@@ -540,8 +540,8 @@ class MDDRCompoundImport(models.Model):
     mddr_name = models.CharField('MDDR name', max_length=40)
     dvpmt_phase = models.CharField(
         'Development phase', max_length=20, choices=MDDR_DEVELOPMENT_PHASES)
-    canonical_smile = models.CharField(
-        'Canonical Smile', max_length=500, blank=True, null=True)
+    canonical_smile = models.TextField(
+        'Canonical Smile', blank=True, null=True)
     # TODO index this table on canonical_smile
     db_import_date = models.DateTimeField('MDDR release year/month')
     activity_classes = models.ManyToManyField(MDDRActivityClass)
@@ -558,10 +558,10 @@ class MDDRCompoundImport(models.Model):
 
 
 class MDDRSimilarity(models.Model):
-    canonical_smile_ippidb = models.CharField(
-        'Canonical Smile for IPPIDB compound', max_length=500, unique=True, blank=True, null=True)
-    canonical_smile_mddr = models.CharField(
-        'Canonical Smile for MDDR Compound', max_length=500, unique=True, blank=True, null=True)
+    canonical_smile_ippidb = models.TextField(
+        'Canonical Smile for IPPIDB compound', unique=True, blank=True, null=True)
+    canonical_smile_mddr = models.TextField(
+        'Canonical Smile for MDDR Compound', unique=True, blank=True, null=True)
     tanimoto = models.DecimalField('Tanimoto', max_digits=6, decimal_places=5)
 
     class Meta: