Molecular Formula: C₁₅H₁₆O₉
Molar mass: 340.2821 g/mol
EINECS: 208-517-5
Density: 1.679 g/cm³
Flash Point: 262.8 °C
Index of Refraction: 1.689
Boiling Point: 697.7 °C at 760 mmHg
Vapour Pressure: 1.97E-20 mmHg at 25°C
Melting point: 203-205 °C
Sensitive: Air Sensitive & Hygroscopic
Solubility: methanol: 50 mg/mL hot, clear to very faintly turbid, yellow-green fluoresc.
Structure of Esculin (66778-17-4):
         
XLogP3-AA: -0.6
H-Bond Donor: 5
H-Bond Acceptor: 9
IUPAC Name: 7-Hydroxy-6-[(2S,5S)-3,4,5-trihydroxy-6-(hydroxymethyl)oxan-2-yl]oxychromen-2-one
Canonical SMILES: C1=CC(=O)OC2=CC(=C(C=C21)OC3C(C(C(C(O3)CO)O)O)O)O
Isomeric SMILES: C1=CC(=O)OC2=CC(=C(C=C21)O[C@H]3C(C([C@@H](C(O3)CO)O)O)O)O
InChI: InChI=1S/C15H16O9/c16-5-10-12(19)13(20)14(21)15(24-10)23-9-3-6-1-2-11
(18)22-8(6)4-7(9)17/h1-4,10,12-17,19-21H,5H2/t10?,12-,13?,14?,15-/m1/s1 
InChIKey: XHCADAYNFIFUHF-WDJGLXJESA-N

 Esculin (66778-17-4) has been used in a microbiology laboratory to aid in the identification of bacterial species.

Carcinogenicity of Esculin (66778-17-4) hasn't been listed as a carcinogen by NTP, IARC,ACGIH, or CA Prop 65. And its toxicological properties have not been fully investigated.You can see actual entry in RTECS for complete information.

Hazard Codes: F,C,Xi
Risk Statements:
11:  Highly Flammable
20:  Harmful by inhalation
21:  Harmful in contact with skin
22:  Harmful if swallowed 
34:  Causes burns
36:  Irritating to the eyes
37:  Irritating to the respiratory system
38:  Irritating to the skin
68:  Possible risk of irreversible effects
Safety Statements:
26:  In case of contact with eyes, rinse immediately with plenty of water and seek medical advice
36:  Wear suitable protective clothing 
37:  Wear suitable gloves
39:  Wear eye/face protection
45:  In case of accident or if you feel unwell, seek medical advice immediately (show label where possible)

 Esculin (66778-17-4) also can be called Esculoside ; aesculin ; 7-Hydroxy-6-glucosyloxy-2H-chromen ; 7-Hydroxy-6-cumarinyl-glucosid ; Aesculetin glukosid .It is incorporated into agar with Ferric citrate and Bile salts ( Bile aesculin agar ).Hydrolysis of the aesculin forms Aesculetin ( 6,7-Dihydroxycoumarin ) and Glucose. The Aesculetin forms dark brown or black complexes withFerric citrate, allowing the test to be read.
It is hazardous,so the first aid measures and others should be known.Such as: When on the skin: first,should  flush skin with plenty of water immediatelyfor at least 15 minutes while removing contaminated clothing. Secondly,Get shoesmedical aid . Or in the eyes: Flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids.Then get medical aid soon.While ,it's Inhaled: Remove from exposure and move to fresh air immediately.Give artificial respiration while not breathing. When breathing is difficult, give oxygen. And as soon as to get medical aid. Then you have the ingesting of the product : Wash mouth out with water,and get medical aid immediately.Notes to physician: Treat supportively and symptomatically.
In addition, Esculin (66778-17-4) is not compatible with strong oxidizing agents, and you must not take it with light, dust generation and incompatible materials.And also prevent it to broken down into hazardous decomposition products: carbon dioxide, carbon monoxide.